KCET 2025 Mathematics Question Paper with Answer and Solution

60 QuestionsEnglishWith Solutions

MathematicsQ160 of 60 questions

Page 1 of 1 · English

1
MathematicsEasyMCQKCET · 2025
Consider the following statements :
Statement $(I)$ : The set of all solutions of the linear inequalities $3x + 8 < 17$ and $2x + 8 \geq 12$ are $x < 3$ and $x \geq 2$ respectively.
Statement $(II)$ : The common set of solutions of linear inequalities $3x + 8 < 17$ and $2x + 8 \geq 12$ is $(2, 3)$.
Which of the following is true?
A
Statement $(I)$ is true but statement $(II)$ is false
B
Statement $(I)$ is false but statement $(II)$ is true
C
Both the statements are true
D
Both the statements are false

Solution

(A) For the first inequality: $3x + 8 < 17$ $\Rightarrow 3x < 9$ $\Rightarrow x < 3$.
For the second inequality: $2x + 8 \geq 12$ $\Rightarrow 2x \geq 4$ $\Rightarrow x \geq 2$.
Thus,Statement $(I)$ is true.
The common set of solutions is the intersection of $x < 3$ and $x \geq 2$,which is the interval $[2, 3)$.
Since Statement $(II)$ claims the set is $(2, 3)$,which excludes $2$,Statement $(II)$ is false.
2
MathematicsEasyMCQKCET · 2025
If $Z_1$ and $Z_2$ are two non-zero complex numbers,then which of the following is not true?
A
$\overline{Z_1+Z_2}=\overline{Z}_1+\overline{Z}_2$
B
$\left|Z_1 Z_2\right|=\left|Z_1\right| \cdot\left|Z_2\right|$
C
$\overline{Z_1 Z_2}=\bar{Z}_1 \cdot \bar{Z}_2$
D
$\left|Z_1+Z_2\right| \geq\left|Z_1\right|+\left|Z_2\right|$

Solution

(D) The triangle inequality for complex numbers states that for any two complex numbers $Z_1$ and $Z_2$,the modulus of their sum is less than or equal to the sum of their moduli,i.e.,$\left|Z_1+Z_2\right| \leq \left|Z_1\right|+\left|Z_2\right|$.
Therefore,the statement $\left|Z_1+Z_2\right| \geq \left|Z_1\right|+\left|Z_2\right|$ is generally false.
3
MathematicsMediumMCQKCET · 2025
The number of four-digit even numbers that can be formed using the digits $0, 1, 2,$ and $3$ without repetition is:
A
$6$
B
$10$
C
$4$
D
$12$

Solution

(B) four-digit number is even if its unit digit is $0$ or $2$. Since repetition is not allowed,we consider two cases:
Case $1$: The unit digit is $0$.
The remaining $3$ positions can be filled by the remaining $3$ digits $(1, 2, 3)$ in $3! = 3 \times 2 \times 1 = 6$ ways.
Case $2$: The unit digit is $2$.
The thousands place cannot be $0$ or $2$. Thus,the thousands place can be filled by $1$ or $3$ ($2$ ways).
The remaining $2$ positions can be filled by the remaining $2$ digits in $2! = 2$ ways.
Total ways for Case $2 = 2 \times 2 = 4$ ways.
Total even numbers = $6 + 4 = 10$.
4
MathematicsEasyMCQKCET · 2025
The number of diagonals that can be drawn in an octagon is
A
$15$
B
$20$
C
$28$
D
$30$

Solution

(B) An octagon has $n = 8$ sides.
The number of diagonals in a polygon with $n$ sides is given by the formula $\frac{n(n-3)}{2}$.
Substituting $n = 8$ into the formula:
$\text{Number of diagonals} = \frac{8(8-3)}{2} = \frac{8 \times 5}{2} = \frac{40}{2} = 20$.
Thus,the number of diagonals is $20$.
5
MathematicsEasyMCQKCET · 2025
If $4^{\text{th}}$,$10^{\text{th}}$,and $16^{\text{th}}$ terms of a $G$.$P$. are $x, y$,and $z$ respectively,then
A
$z=\sqrt{xy}$
B
$y=\sqrt{xz}$
C
$x=\sqrt{yz}$
D
$y=\frac{x+z}{2}$

Solution

(B) Let the first term of the $G$.$P$. be $a$ and the common ratio be $r$.
The $n^{\text{th}}$ term of a $G$.$P$. is given by $T_n = ar^{n-1}$.
Given:
$x = T_4 = ar^3$
$y = T_{10} = ar^9$
$z = T_{16} = ar^{15}$
Now,consider the product $xz$:
$xz = (ar^3)(ar^{15}) = a^2r^{18} = (ar^9)^2$
Since $y = ar^9$,we have $xz = y^2$.
Therefore,$y = \sqrt{xz}$.
6
MathematicsEasyMCQKCET · 2025
If the number of terms in the binomial expansion of $(2x + 3)^{3n}$ is $22$,then the value of $n$ is:
A
$8$
B
$6$
C
$7$
D
$9$

Solution

(C) The number of terms in the binomial expansion of $(a + b)^m$ is given by $m + 1$.
Given the expression $(2x + 3)^{3n}$,the number of terms is $(3n + 1)$.
According to the problem,the number of terms is $22$.
So,$3n + 1 = 22$.
$3n = 21$.
$n = 7$.
7
MathematicsEasyMCQKCET · 2025
Which of the following is not correct?
A
$\cos 5 \pi = \cos 4 \pi$
B
$\sin 2 \pi = \sin (-2 \pi)$
C
$\sin 4 \pi = \sin 6 \pi$
D
$\tan 45^{\circ} = \tan (-315^{\circ})$

Solution

(A) We evaluate each option:
$A$: $\cos 5 \pi = -1$ and $\cos 4 \pi = 1$. Since $-1 \neq 1$,this statement is incorrect.
$B$: $\sin 2 \pi = 0$ and $\sin (-2 \pi) = 0$. This is correct.
$C$: $\sin 4 \pi = 0$ and $\sin 6 \pi = 0$. This is correct.
$D$: $\tan 45^{\circ} = 1$ and $\tan (-315^{\circ}) = \tan (-315^{\circ} + 360^{\circ}) = \tan 45^{\circ} = 1$. This is correct.
Therefore,the incorrect statement is $A$.
8
MathematicsEasyMCQKCET · 2025
If $\cos x + \cos^2 x = 1$,then the value of $\sin^2 x + \sin^4 x$ is
A
$-1$
B
$1$
C
$0$
D
$2$

Solution

(B) Given that $\cos x + \cos^2 x = 1$.
From this,we have $\cos x = 1 - \cos^2 x$.
Using the identity $\sin^2 x + \cos^2 x = 1$,we get $\sin^2 x = \cos x$.
Now,we need to find the value of $\sin^2 x + \sin^4 x$.
Substituting $\sin^2 x = \cos x$,we get $\sin^2 x + \sin^4 x = \cos x + (\cos x)^2$.
Since $\cos x + \cos^2 x = 1$,the value is $1$.
9
MathematicsEasyMCQKCET · 2025
The minimum value of $1-\sin x$ is
A
$0$
B
$-1$
C
$1$
D
$2$

Solution

(A) We know that the range of the sine function is $-1 \leq \sin x \leq 1$.
To find the minimum value of $f(x) = 1 - \sin x$,we need to subtract the maximum possible value of $\sin x$ from $1$.
Since the maximum value of $\sin x$ is $1$,we have:
$f_{\min} = 1 - (\sin x)_{\max} = 1 - 1 = 0$.
10
MathematicsEasyMCQKCET · 2025
$A$ line passes through $(-1, -3)$ and is perpendicular to $x + 6y = 5$. Its $x$-intercept is
A
$\frac{1}{2}$
B
$-\frac{1}{2}$
C
$-2$
D
$2$

Solution

(B) The given line is $x + 6y = 5$,which can be written as $y = -\frac{1}{6}x + \frac{5}{6}$.
The slope of this line is $m_1 = -\frac{1}{6}$.
Since the required line is perpendicular to this line,its slope $m_2$ must satisfy $m_1 \times m_2 = -1$.
Thus,$m_2 = -\frac{1}{m_1} = -\frac{1}{-1/6} = 6$.
The equation of the line passing through $(-1, -3)$ with slope $m = 6$ is given by $y - y_1 = m(x - x_1)$.
$y - (-3) = 6(x - (-1))$
$y + 3 = 6(x + 1)$
$y + 3 = 6x + 6$
$6x - y = -3$.
To find the $x$-intercept,we set $y = 0$ in the equation:
$6x - 0 = -3$
$6x = -3$
$x = -\frac{3}{6} = -\frac{1}{2}$.
Solution diagram
11
MathematicsEasyMCQKCET · 2025
The length of the latus rectum of $x^2+3y^2=12$ is
A
$\frac{2}{3}$ units
B
$\frac{1}{3}$ units
C
$\frac{4}{\sqrt{3}}$ units
D
$24$ units

Solution

(C) Given equation: $x^2+3y^2=12$
Divide by $12$: $\frac{x^2}{12} + \frac{y^2}{4} = 1$
This is an ellipse of the form $\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1$,where $a^2 = 12$ and $b^2 = 4$.
Thus,$a = \sqrt{12} = 2\sqrt{3}$ and $b = 2$.
The length of the latus rectum is given by $\frac{2b^2}{a}$.
Length $= \frac{2 \times 4}{2\sqrt{3}} = \frac{4}{\sqrt{3}}$ units.
12
MathematicsMediumMCQKCET · 2025
The value of $\lim _{x \rightarrow 1} \frac{x^4-\sqrt{x}}{\sqrt{x}-1}$ is
A
$0$
B
$7$
C
Does not exist
D
$\frac{1}{2}$

Solution

(B) Let $L = \lim _{x \rightarrow 1} \frac{x^4-\sqrt{x}}{\sqrt{x}-1}$.
Since the limit is in the $\frac{0}{0}$ form,we apply $L'H\hat{o}pital's$ rule:
$L = \lim _{x \rightarrow 1} \frac{\frac{d}{dx}(x^4-\sqrt{x})}{\frac{d}{dx}(\sqrt{x}-1)}$
$L = \lim _{x \rightarrow 1} \frac{4x^3 - \frac{1}{2\sqrt{x}}}{\frac{1}{2\sqrt{x}}}$
$L = \lim _{x}$ ${\rightarrow 1} \left( \frac{4x^3}{\frac{1}{2\sqrt{x}}} - \frac{\frac{1}{2\sqrt{x}}}{\frac{1}{2\sqrt{x}}} \right)$
$L = \lim _{x \rightarrow 1} (8x^3\sqrt{x} - 1)$
$L = 8(1)^3\sqrt{1} - 1 = 8 - 1 = 7$.
13
MathematicsMediumMCQKCET · 2025
The mean deviation about the mean for the data $4, 7, 8, 9, 10, 12, 13, 17$ is
A
$10$
B
$3$
C
$8.5$
D
$4.03$

Solution

(B) Step $1$: Calculate the mean $(\mu)$ of the data.
$\mu = \frac{4+7+8+9+10+12+13+17}{8} = \frac{80}{8} = 10$.
Step $2$: Calculate the mean deviation about the mean using the formula $\frac{1}{N} \sum |x_i - \mu|$.
$|4-10| = 6$
$|7-10| = 3$
$|8-10| = 2$
$|9-10| = 1$
$|10-10| = 0$
$|12-10| = 2$
$|13-10| = 3$
$|17-10| = 7$
Sum of absolute deviations $= 6+3+2+1+0+2+3+7 = 24$.
Mean deviation $= \frac{24}{8} = 3$.
14
MathematicsEasyMCQKCET · 2025
$A$ and $B$ are two sets having $3$ and $6$ elements respectively. Consider the following statements. Statement $(I)$: Minimum number of elements in $A \cup B$ is $6$. Statement $(II)$: Maximum number of elements in $A \cap B$ is $3$. Which of the following is correct?
A
Statement $(I)$ is true,statement $(II)$ is false
B
Statement $(I)$ is false,statement $(II)$ is true
C
Both statements $(I)$ and $(II)$ are true
D
Both statements $(I)$ and $(II)$ are false

Solution

(C) Given $|A| = 3$ and $|B| = 6$.
For $A \cup B$,the formula is $|A \cup B| = |A| + |B| - |A \cap B|$.
To minimize $|A \cup B|$,we must maximize $|A \cap B|$. The maximum value of $|A \cap B|$ is $\min(|A|, |B|) = 3$.
Thus,$\min |A \cup B| = 3 + 6 - 3 = 6$. So,Statement $(I)$ is true.
For $A \cap B$,the maximum value is $\min(|A|, |B|) = 3$.
Thus,$\max |A \cap B| = 3$. So,Statement $(II)$ is true.
15
MathematicsEasyMCQKCET · 2025
If $A = \{ x : x \text{ is an integer and } x^2 - 9 = 0 \}$,$B = \{ x : x \text{ is a natural number and } 2 \leq x < 5 \}$,and $C = \{ x : x \text{ is a prime number } \leq 4 \}$,then $(B - C) \cup A$ is:
A
$\{ -3, 3, 4 \}$
B
$\{ 2, 3, 4 \}$
C
$\{ 3, 4, 5 \}$
D
$\{ 2, 3, 5 \}$

Solution

(A) First,we determine the elements of each set:
$A = \{ x : x \text{ is an integer and } x^2 - 9 = 0 \} = \{ -3, 3 \}$.
$B = \{ x : x \text{ is a natural number and } 2 \leq x < 5 \} = \{ 2, 3, 4 \}$.
$C = \{ x : x \text{ is a prime number } \leq 4 \} = \{ 2, 3 \}$.
Next,calculate $(B - C)$:
$B - C = \{ 2, 3, 4 \} - \{ 2, 3 \} = \{ 4 \}$.
Finally,calculate $(B - C) \cup A$:
$(B - C) \cup A = \{ 4 \} \cup \{ -3, 3 \} = \{ -3, 3, 4 \}$.
16
MathematicsEasyMCQKCET · 2025
The system of equations $4x + 6y = 5$ and $8x + 12y = 10$ has
A
No solution
B
Infinitely many solutions
C
$A$ unique solution
D
Only two solutions

Solution

(B) Given equations are:
$1. 4x + 6y = 5$
$2. 8x + 12y = 10$
Step-by-step check:
Multiply Equation $(1)$ by $2$:
$2(4x + 6y) = 2(5) \Rightarrow 8x + 12y = 10$
Comparing this with Equation $(2)$,we see that both equations are identical.
Conclusion:
Since both equations represent the same line,the system has infinitely many solutions.
17
MathematicsEasyMCQKCET · 2025
The distance of the point $P(-3, 4, 5)$ from the $yz$-plane is: (in $\text{ units}$)
A
$4$
B
$5$
C
$-3$
D
$3$

Solution

(D) The distance of a point $P(x, y, z)$ from the $yz$-plane is given by the absolute value of its $x$-coordinate,which is $|x|$.
Given the point $P(-3, 4, 5)$,the $x$-coordinate is $-3$.
Therefore,the distance from the $yz$-plane is $|-3| = 3 \text{ units}$.
Thus,the correct option is $D$.
18
MathematicsEasyMCQKCET · 2025
$A$ random experiment has five outcomes $w_1, w_2, w_3, w_4$ and $w_5$. The probabilities of the occurrence of the outcomes $w_1, w_2, w_3, w_4$ and $w_5$ are respectively $\frac{1}{6}, a, b, c$ and $\frac{1}{12}$ such that $12a + 12b - 1 = 0$. If $p(w_4) = c$ and the outcomes are equally likely for $w_2, w_3, w_4$,find the probability of the outcome $w_3$. Given the condition $12a + 12b = 1$,and assuming $a=b=c$ for the remaining outcomes,find $p(w_3)$.
A
$\frac{2}{3}$
B
$\frac{1}{3}$
C
$\frac{1}{6}$
D
$\frac{1}{12}$

Solution

(C) The sum of probabilities of all outcomes in a random experiment is $1$.
$p(w_1) + p(w_2) + p(w_3) + p(w_4) + p(w_5) = 1$.
Given $p(w_1) = \frac{1}{6}$,$p(w_2) = a$,$p(w_3) = b$,$p(w_4) = c$,and $p(w_5) = \frac{1}{12}$.
So,$\frac{1}{6} + a + b + c + \frac{1}{12} = 1$.
$\frac{2+1}{12} + a + b + c = 1$ $\Rightarrow \frac{3}{12} + a + b + c = 1$ $\Rightarrow a + b + c = 1 - \frac{1}{4} = \frac{3}{4}$.
Given $12a + 12b - 1 = 0$,we have $a + b = \frac{1}{12}$.
Substituting this into the sum: $\frac{1}{12} + c = \frac{3}{4} \Rightarrow c = \frac{3}{4} - \frac{1}{12} = \frac{9-1}{12} = \frac{8}{12} = \frac{2}{3}$.
Assuming the outcomes $w_2, w_3$ are equally likely,$a = b$.
Since $a + b = \frac{1}{12}$,then $2b = \frac{1}{12} \Rightarrow b = \frac{1}{24}$.
However,based on the provided options and standard interpretation of such problems where $a=b=c$ is not implied but specific constraints are given,the intended answer is $p(w_3) = \frac{1}{24}$ which is not listed. Re-evaluating the prompt's constraint $12a+12b=1$,if $a=b$,then $b = \frac{1}{24}$. If the question implies $p(w_3) = b = \frac{1}{24}$,none match. Given the structure,if $a=b=c$,then $3b = 3/4 \Rightarrow b = 1/4$. If $12a+12b=1$ and $a=b$,$24b=1 \Rightarrow b=1/24$. Given the options,$b = 1/24$ is not present. Assuming a typo in the question where $12a+12b=1$ was meant to be $a+b=...$,we select the most logical fit.
19
MathematicsEasyMCQKCET · 2025
$A$ die has two faces each with number $1$,three faces each with number $2$,and one face with number $3$. If the die is rolled once,then $P(1 \text{ or } 3)$ is
A
$\frac{2}{3}$
B
$\frac{1}{2}$
C
$\frac{1}{3}$
D
$\frac{1}{6}$

Solution

(B) The total number of faces on the die is $2 + 3 + 1 = 6$.
The probability of getting a $1$ is $P(1) = \frac{2}{6}$.
The probability of getting a $3$ is $P(3) = \frac{1}{6}$.
Since the events are mutually exclusive,$P(1 \text{ or } 3) = P(1) + P(3) = \frac{2}{6} + \frac{1}{6} = \frac{3}{6} = \frac{1}{2}$.
20
MathematicsEasyMCQKCET · 2025
If $A$ and $B$ are two events such that $A \subset B$ and $P(B) \neq 0$,then which of the following is correct?
A
$P(A \mid B) = \frac{P(B)}{P(A)}$
B
$P(A \mid B) < P(A)$
C
$P(A \mid B) \geq P(A)$
D
None of these

Solution

(C) Given that $A \subset B$,it implies that $A \cap B = A$.
By the definition of conditional probability,$P(A \mid B) = \frac{P(A \cap B)}{P(B)}$.
Substituting $A \cap B = A$,we get $P(A \mid B) = \frac{P(A)}{P(B)}$.
Since $A \subset B$,we have $P(A) \leq P(B)$,which implies $\frac{1}{P(B)} \leq \frac{1}{P(A)}$.
Multiplying both sides by $P(A)$ (assuming $P(A) > 0$),we get $\frac{P(A)}{P(B)} \leq 1$.
Also,since $P(B) \leq 1$,we have $\frac{P(A)}{P(B)} \geq P(A)$.
Thus,$P(A \mid B) \geq P(A)$.
21
MathematicsMediumMCQKCET · 2025
Let $A = \{a, b, c\}$. The number of equivalence relations on $A$ containing $(b, c)$ is:
A
$1$
B
$3$
C
$2$
D
$4$

Solution

(C) An equivalence relation $R$ on $A = \{a, b, c\}$ must be reflexive,symmetric,and transitive. Since $(b, c) \in R$ and $R$ is symmetric,$(c, b) \in R$. Since $R$ is reflexive,$(a, a), (b, b), (c, c) \in R$.
For transitivity,since $(b, c) \in R$ and $(c, b) \in R$,we must have $(b, b) \in R$ (which is true) and $(c, c) \in R$ (which is true).
Case $1$: If $a$ is related only to itself,$R_1 = \{(a, a), (b, b), (c, c), (b, c), (c, b)\}$. This is an equivalence relation.
Case $2$: If $a$ is related to $b$ and $c$,then by symmetry and transitivity,$a$ must be related to all elements. $R_2 = \{(a, a), (b, b), (c, c), (a, b), (b, a), (a, c), (c, a), (b, c), (c, b)\}$. This is the universal relation,which is also an equivalence relation.
Thus,there are $2$ such equivalence relations.
22
MathematicsEasyMCQKCET · 2025
If $A$ is a square matrix such that $A^2=A$,then $(I-A)^3$ is
A
$I-A$
B
$A-I$
C
$I+A$
D
$-I-A$

Solution

(A) Given that $A^2=A$.
We need to evaluate $(I-A)^3$.
Using the binomial expansion for matrices,$(I-A)^3 = I^3 - 3I^2A + 3IA^2 - A^3$.
Since $I^n = I$ and $A^2 = A$,we have $A^3 = A^2 \times A = A \times A = A^2 = A$.
Substituting these values:
$(I-A)^3 = I - 3A + 3A - A$.
$(I-A)^3 = I - A$.
23
MathematicsEasyMCQKCET · 2025
If $A$ and $B$ are two matrices such that $AB$ is an identity matrix and the order of matrix $B$ is $3 \times 4$,then the order of matrix $A$ is
A
$3 \times 4$
B
$3 \times 3$
C
$4 \times 3$
D
$4 \times 4$

Solution

(C) For the product $AB$ to be an identity matrix $I$,the number of columns in $A$ must be equal to the number of rows in $B$,and the resulting matrix $AB$ must be a square matrix.
Given that the order of matrix $B$ is $3 \times 4$,let the order of matrix $A$ be $m \times n$.
For the product $AB$ to be defined,the number of columns in $A$ $(n)$ must equal the number of rows in $B$ $(3)$. Thus,$n = 3$.
The resulting matrix $AB$ will have the order $m \times 4$.
Since $AB$ is an identity matrix,it must be a square matrix,meaning the number of rows must equal the number of columns. Therefore,$m = 4$.
Thus,the order of matrix $A$ is $4 \times 3$.
24
MathematicsMediumMCQKCET · 2025
If a matrix $A = \begin{bmatrix} 1 & 1 \\ 1 & 1 \end{bmatrix}$ satisfies $A^6 = k A$,then the value of $k$ is
A
$32$
B
$1$
C
$\frac{1}{32}$
D
$6$

Solution

(A) Given $A = \begin{bmatrix} 1 & 1 \\ 1 & 1 \end{bmatrix}$.
Calculate powers of $A$:
$A^2 = \begin{bmatrix} 1 & 1 \\ 1 & 1 \end{bmatrix} \begin{bmatrix} 1 & 1 \\ 1 & 1 \end{bmatrix} = \begin{bmatrix} 2 & 2 \\ 2 & 2 \end{bmatrix} = 2^1 A$.
$A^3 = A^2 \cdot A = \begin{bmatrix} 2 & 2 \\ 2 & 2 \end{bmatrix} \begin{bmatrix} 1 & 1 \\ 1 & 1 \end{bmatrix} = \begin{bmatrix} 4 & 4 \\ 4 & 4 \end{bmatrix} = 2^2 A$.
By induction,$A^n = 2^{n-1} A$.
For $n = 6$,$A^6 = 2^{6-1} A = 2^5 A = 32 A$.
Comparing $A^6 = k A$ with $A^6 = 32 A$,we get $k = 32$.
25
MathematicsEasyMCQKCET · 2025
Which of the following statements is not correct?
A
$A$ row matrix has only one row
B
$A$ diagonal matrix has all diagonal elements equal to zero
C
$A$ symmetric matrix $A$ is a square matrix satisfying $A^{\prime}=A$.
D
$A$ skew symmetric matrix has all diagonal elements equal to zero

Solution

(B) diagonal matrix is a square matrix in which all elements except those in the main diagonal are zero. The diagonal elements themselves can be any value,including zero,but they are not required to be zero. Therefore,the statement that a diagonal matrix has all diagonal elements equal to zero is incorrect.
26
MathematicsMediumMCQKCET · 2025
If $B=\left[\begin{array}{ll}1 & 3 \\ 1 & \alpha\end{array}\right]$ is the adjoint of a matrix $A$ and $|A|=2$,then the value of $\alpha$ is
A
$4$
B
$5$
C
$2$
D
$3$

Solution

(B) We know that for any square matrix $A$,the property relating the adjoint and the determinant is $|\operatorname{adj}(A)| = |A|^{n-1}$,where $n$ is the order of the matrix.
Here,$n=2$ and $|A|=2$.
So,$|\operatorname{adj}(A)| = |A|^{2-1} = |A|^1 = 2$.
Given $\operatorname{adj}(A) = B = \left[\begin{array}{ll}1 & 3 \\ 1 & \alpha\end{array}\right]$,we calculate the determinant of $B$:
$|B| = (1)(\alpha) - (3)(1) = \alpha - 3$.
Since $|\operatorname{adj}(A)| = |B|$,we have $\alpha - 3 = 2$.
Therefore,$\alpha = 2 + 3 = 5$.
27
MathematicsEasyMCQKCET · 2025
If $A$ is a square matrix satisfying the equation $A^2 - 5A + 7I = 0$,where $I$ is the identity matrix and $0$ is the null matrix of the same order,then $A^{-1} = $
A
$\frac{1}{7}(5I - A)$
B
$\frac{1}{7}(A - 5I)$
C
$7(5I - A)$
D
$\frac{1}{5}(7I - A)$

Solution

(A) Given the equation: $A^2 - 5A + 7I = 0$.
Since $A^2 - 5A + 7I = 0$,we have $7I = 5A - A^2$.
Multiplying both sides by $A^{-1}$ (assuming $|A| \neq 0$):
$A^{-1}(A^2 - 5A + 7I) = A^{-1}(0)$.
$A^{-1}A^2 - 5A^{-1}A + 7A^{-1}I = 0$.
$A - 5I + 7A^{-1} = 0$.
$7A^{-1} = 5I - A$.
$A^{-1} = \frac{1}{7}(5I - A)$.
28
MathematicsEasyMCQKCET · 2025
If $A = \begin{bmatrix} k & 2 \\ 2 & k \end{bmatrix}$ and $|A^3| = 125$,then the value of $k$ is
A
$\pm 2$
B
$\pm 3$
C
$-5$
D
$-4$

Solution

(B) Given $A = \begin{bmatrix} k & 2 \\ 2 & k \end{bmatrix}$.
First,calculate the determinant of $A$:
$|A| = (k \times k) - (2 \times 2) = k^2 - 4$.
We know the property of determinants that $|A^n| = |A|^n$.
Given $|A^3| = 125$,we can write this as $|A|^3 = 125$.
Substituting the value of $|A|$:
$(k^2 - 4)^3 = 125$.
Taking the cube root on both sides:
$k^2 - 4 = 5$.
$k^2 = 9$.
$k = \pm 3$.
29
MathematicsMediumMCQKCET · 2025
If $A$ is a square matrix of order $3 \times 3$ and $\operatorname{det}(A) = 3$,then the value of $\operatorname{det}(3A^{-1})$ is:
A
$1/3$
B
$3$
C
$27$
D
$9$

Solution

(D) Given that $A$ is a square matrix of order $n = 3$ and $\operatorname{det}(A) = 3$.
We know that for a scalar $k$ and an $n \times n$ matrix $A$,$\operatorname{det}(kA) = k^n \operatorname{det}(A)$.
Also,$\operatorname{det}(A^{-1}) = \frac{1}{\operatorname{det}(A)}$.
Therefore,$\operatorname{det}(3A^{-1}) = 3^3 \operatorname{det}(A^{-1})$.
Substituting the values,we get $\operatorname{det}(3A^{-1}) = 27 \times \frac{1}{\operatorname{det}(A)} = 27 \times \frac{1}{3} = 9$.
30
MathematicsMediumMCQKCET · 2025
$2 \cos ^{-1} x = \sin ^{-1} \left( 2 x \sqrt{1 - x^2} \right)$ is valid for all values of $x$ satisfying:
A
$0 \leq x \leq \frac{1}{\sqrt{2}}$
B
$-1 \leq x \leq 1$
C
$0 \leq x \leq 1$
D
$\frac{1}{\sqrt{2}} \leq x \leq 1$

Solution

(D) Let $x = \cos \theta$,where $\theta = \cos^{-1} x$. Since $x \in [-1, 1]$,$\theta \in [0, \pi]$.
Substituting $x = \cos \theta$ into the right-hand side:
$\sin^{-1} (2 \cos \theta \sqrt{1 - \cos^2 \theta}) = \sin^{-1} (2 \cos \theta \sin \theta) = \sin^{-1} (\sin 2 \theta)$.
For this to equal $2 \cos^{-1} x = 2 \theta$,we require $\sin^{-1} (\sin 2 \theta) = 2 \theta$.
This holds when $2 \theta \in [-\frac{\pi}{2}, \frac{\pi}{2}]$,which implies $\theta \in [-\frac{\pi}{4}, \frac{\pi}{4}]$.
Given $\theta \in [0, \pi]$,the intersection is $\theta \in [0, \frac{\pi}{4}]$.
Since $\theta = \cos^{-1} x$,we have $0 \leq \cos^{-1} x \leq \frac{\pi}{4}$.
Taking the cosine of all sides (noting that $\cos$ is a decreasing function in this interval):
$\cos(0) \geq x \geq \cos(\frac{\pi}{4})$,
which gives $1 \geq x \geq \frac{1}{\sqrt{2}}$ or $\frac{1}{\sqrt{2}} \leq x \leq 1$.
31
MathematicsEasyMCQKCET · 2025
$\sec ^2(\tan ^{-1} 2)+\operatorname{cosec}^2(\cot ^{-1} 3) = $
A
$1$
B
$5$
C
$15$
D
$10$

Solution

(C) We use the trigonometric identities $\sec ^2 \theta = 1 + \tan ^2 \theta$ and $\operatorname{cosec}^2 \theta = 1 + \cot ^2 \theta$.
Substituting $\theta = \tan ^{-1} 2$ and $\theta = \cot ^{-1} 3$ respectively:
$= (1 + \tan ^2(\tan ^{-1} 2)) + (1 + \cot ^2(\cot ^{-1} 3))$
$= (1 + (\tan(\tan ^{-1} 2))^2) + (1 + (\cot(\cot ^{-1} 3))^2)$
$= (1 + 2^2) + (1 + 3^2)$
$= (1 + 4) + (1 + 9)$
$= 5 + 10 = 15$.
32
MathematicsEasyMCQKCET · 2025
Domain of the function $f$,given by $f(x) = \frac{1}{\sqrt{(x - 2)(x - 5)}}$ is
A
$(-\infty, 2] \cup [5, \infty)$
B
$(-\infty, 2) \cup (5, \infty)$
C
$(-\infty, 3) \cup [5, \infty)$
D
$(-\infty, 3] \cup (5, \infty)$

Solution

(B) For the function $f(x) = \frac{1}{\sqrt{(x - 2)(x - 5)}}$ to be defined,the expression inside the square root must be strictly greater than zero.
$\Rightarrow (x - 2)(x - 5) > 0$
The critical points are $x = 2$ and $x = 5$.
Testing the intervals $(-\infty, 2)$,$(2, 5)$,and $(5, \infty)$:
For $x < 2$,$(x - 2)(x - 5) > 0$.
For $2 < x < 5$,$(x - 2)(x - 5) < 0$.
For $x > 5$,$(x - 2)(x - 5) > 0$.
Thus,the domain is $x \in (-\infty, 2) \cup (5, \infty)$.
33
MathematicsMediumMCQKCET · 2025
If $f(x) = \sin([\pi^2]x) - \sin([-\pi^2]x)$,where $[x]$ denotes the greatest integer function $\leq x$,then which of the following is not true?
A
$f(0) = 0$
B
$f(\frac{\pi}{2}) = \sin(\frac{9\pi}{2}) + \sin(5\pi) = 1 + 0 = 1$
C
$f(\frac{\pi}{4}) = \sin(\frac{9\pi}{4}) + \sin(\frac{5\pi}{2}) = \frac{1}{\sqrt{2}} + 1$
D
$f(\pi) = -1$

Solution

(D) Given $f(x) = \sin([\pi^2]x) - \sin([-\pi^2]x)$.
Since $\pi^2 \approx 9.869$,we have $[\pi^2] = 9$.
Since $-\pi^2 \approx -9.869$,we have $[-\pi^2] = -10$.
Thus,$f(x) = \sin(9x) - \sin(-10x) = \sin(9x) + \sin(10x)$.
Check options:
$A) f(0) = \sin(0) + \sin(0) = 0$ (True).
$B) f(\frac{\pi}{2}) = \sin(\frac{9\pi}{2}) + \sin(5\pi) = 1 + 0 = 1$ (True).
$C) f(\frac{\pi}{4}) = \sin(\frac{9\pi}{4}) + \sin(\frac{10\pi}{4}) = \sin(\frac{\pi}{4}) + \sin(\frac{5\pi}{2}) = \frac{1}{\sqrt{2}} + 1$ (True).
$D) f(\pi) = \sin(9\pi) + \sin(10\pi) = 0 + 0 = 0$. Since $0 \neq -1$,this statement is not true.
34
MathematicsMediumMCQKCET · 2025
Let the functions $f$ and $g$ be $f: [0, \frac{\pi}{2}] \rightarrow R$ given by $f(x) = \sin x$ and $g: [0, \frac{\pi}{2}] \rightarrow R$ given by $g(x) = \cos x$,where $R$ is the set of real numbers. Consider the following statements:
Statement $(I)$: $f$ and $g$ are one-one.
Statement $(II)$: $f+g$ is one-one.
Which of the following is correct?
A
Statement $(I)$ is true,statement $(II)$ is false
B
Statement $(I)$ is false,statement $(II)$ is true
C
Both statements $(I)$ and $(II)$ are true
D
Both statements $(I)$ and $(II)$ are false

Solution

(A) For $f(x) = \sin x$ on $[0, \frac{\pi}{2}]$,the function is strictly increasing,so it is one-one.
For $g(x) = \cos x$ on $[0, \frac{\pi}{2}]$,the function is strictly decreasing,so it is one-one.
Thus,Statement $(I)$ is true.
Now,consider $(f+g)(x) = \sin x + \cos x$.
We evaluate the function at the endpoints of the interval:
$(f+g)(0) = \sin(0) + \cos(0) = 0 + 1 = 1$.
$(f+g)(\frac{\pi}{2}) = \sin(\frac{\pi}{2}) + \cos(\frac{\pi}{2}) = 1 + 0 = 1$.
Since $(f+g)(0) = (f+g)(\frac{\pi}{2})$ but $0 \neq \frac{\pi}{2}$,the function $f+g$ is not one-one.
Thus,Statement $(II)$ is false.
35
MathematicsMediumMCQKCET · 2025
Match the following:
In the following,$[x]$ denotes the greatest integer less than or equal to $x$.
$(a)$ $x|x|$$(i)$ continuous in $(-1, 1)$
$(b)$ $\sqrt{|x|}$$(ii)$ differentiable in $(-1, 1)$
$(c)$ $x+[x]$$(iii)$ strictly increasing in $(-1, 1)$
$(d)$ $|x-1|+|x+1|$$(iv)$ not differentiable at,at least one point in $(-1, 1)$
A
$a-(i), b-(ii), c-(iv), d-(iii)$
B
$a-(iv), b-(iii), c-(i), d-(ii)$
C
$a-(ii), b-(iv), c-(iii), d-(i)$
D
$a-(iii), b-(ii), c-(iv), d-(i)$

Solution

(C) $f(x) = x|x| = \begin{cases} x^2, & x \geq 0 \\ -x^2, & x < 0 \end{cases}$. The derivative $f'(x) = 2|x|$ exists for all $x$,so it is differentiable in $(-1, 1)$. Thus,$(a) \to (ii)$.
$(b)$ $f(x) = \sqrt{|x|}$. At $x=0$,the left-hand derivative is $\lim_{h \to 0^-} \frac{\sqrt{-h}-0}{h} = -\infty$ and right-hand derivative is $\infty$. Thus,it is not differentiable at $x=0$,which is in $(-1, 1)$. Thus,$(b) \to (iv)$.
$(c)$ $f(x) = x+[x]$. This function is strictly increasing in $(-1, 1)$ because $x$ is strictly increasing and $[x]$ is non-decreasing. Thus,$(c) \to (iii)$.
$(d)$ $f(x) = |x-1|+|x+1|$. In $(-1, 1)$,$f(x) = -(x-1) + (x+1) = 2$,which is a constant function and therefore continuous in $(-1, 1)$. Thus,$(d) \to (i)$.
The correct matching is $a-(ii), b-(iv), c-(iii), d-(i)$.
Solution diagram
36
MathematicsMediumMCQKCET · 2025
$A$ function is $f(x) = \begin{cases} \frac{e^{1/x}-1}{e^{1/x}+1}, & \text{if } x \neq 0 \\ 0, & \text{if } x=0 \end{cases}$
A
continuous at $x=0$
B
not continuous at $x=0$
C
differentiable at $x=0$
D
differentiable at $x=0$,but not continuous at $x=0$

Solution

(B) To check the continuity at $x=0$,we evaluate the left-hand limit $(LHL)$ and right-hand limit $(RHL)$.
For $LHL$: $\lim_{x \to 0^-} f(x) = \lim_{h \to 0} \frac{e^{1/(0-h)}-1}{e^{1/(0-h)}+1} = \lim_{h \to 0} \frac{e^{-1/h}-1}{e^{-1/h}+1}$. Since $e^{-1/h} \to 0$ as $h \to 0^+$,$LHL$ $= \frac{0-1}{0+1} = -1$.
For $RHL$: $\lim_{x \to 0^+} f(x) = \lim_{h \to 0} \frac{e^{1/h}-1}{e^{1/h}+1} = \lim_{h \to 0} \frac{1-e^{-1/h}}{1+e^{-1/h}} = \frac{1-0}{1+0} = 1$.
Since $LHL$ $\neq$ $RHL$,the limit does not exist at $x=0$.
Therefore,the function is not continuous at $x=0$.
37
MathematicsMediumMCQKCET · 2025
The function $f(x) = \begin{cases} e^x + ax, & x < 0 \\ b(x - 1)^2, & x \geq 0 \end{cases}$ is differentiable at $x = 0$. Then
A
$a = 1, b = 1$
B
$a = 3, b = 1$
C
$a = -3, b = 1$
D
$a = 3, b = -1$

Solution

(C) For $f(x)$ to be differentiable at $x = 0$,it must first be continuous at $x = 0$.
Left-hand limit $(LHL)$: $\lim_{x \to 0^-} f(x) = \lim_{x \to 0^-} (e^x + ax) = e^0 + a(0) = 1$.
Right-hand limit $(RHL)$: $\lim_{x \to 0^+} f(x) = \lim_{x \to 0^+} b(x - 1)^2 = b(0 - 1)^2 = b$.
Since $f(x)$ is continuous,$LHL = RHL$,so $b = 1$.
Now,for differentiability,the left-hand derivative $(LHD)$ must equal the right-hand derivative $(RHD)$ at $x = 0$.
$LHD = \lim_{x \to 0^-} f'(x) = \lim_{x \to 0^-} (e^x + a) = e^0 + a = 1 + a$.
$RHD = \lim_{x \to 0^+} f'(x) = \lim_{x \to 0^+} 2b(x - 1) = 2b(0 - 1) = -2b$.
Equating $LHD$ and $RHD$: $1 + a = -2b$.
Substituting $b = 1$: $1 + a = -2(1) \Rightarrow 1 + a = -2 \Rightarrow a = -3$.
Thus,$a = -3$ and $b = 1$.
38
MathematicsMediumMCQKCET · 2025
If $y=\frac{\cos x}{1+\sin x}$,then
$(a)$ $\frac{dy}{dx}=\frac{-1}{1+\sin x}$
$(b)$ $\frac{dy}{dx}=\frac{1}{1+\sin x}$
$(c)$ $\frac{dy}{dx}=-\frac{1}{2} \sec ^2\left(\frac{\pi}{4}-\frac{x}{2}\right)$
$(d)$ $\frac{dy}{dx}=\frac{1}{2} \sec ^2\left(\frac{\pi}{4}-\frac{x}{2}\right)$
A
Only $b$ is correct
B
Only $a$ is correct
C
Both $a$ and $c$ are correct
D
Both $b$ and $d$ are correct

Solution

(C) Given $y = \frac{\cos x}{1+\sin x}$.
Using the quotient rule $\frac{d}{dx}\left(\frac{u}{v}\right) = \frac{u'v - uv'}{v^2}$:
$\frac{dy}{dx} = \frac{(-\sin x)(1+\sin x) - (\cos x)(\cos x)}{(1+\sin x)^2}$
$\frac{dy}{dx} = \frac{-\sin x - \sin^2 x - \cos^2 x}{(1+\sin x)^2} = \frac{-(\sin x + \sin^2 x + \cos^2 x)}{(1+\sin x)^2}$
Since $\sin^2 x + \cos^2 x = 1$,we have:
$\frac{dy}{dx} = \frac{-(1+\sin x)}{(1+\sin x)^2} = \frac{-1}{1+\sin x}$. This matches option $(a)$.
Now,simplify $\frac{-1}{1+\sin x}$ using trigonometric identities:
$1+\sin x = 1+\cos\left(\frac{\pi}{2}-x\right) = 2\cos^2\left(\frac{\pi}{4}-\frac{x}{2}\right)$.
Therefore,$\frac{dy}{dx} = \frac{-1}{2\cos^2\left(\frac{\pi}{4}-\frac{x}{2}\right)} = -\frac{1}{2}\sec^2\left(\frac{\pi}{4}-\frac{x}{2}\right)$. This matches option $(c)$.
Thus,both $(a)$ and $(c)$ are correct.
39
MathematicsMediumMCQKCET · 2025
If $y=a \sin ^3 t$ and $x=a \cos ^3 t$,then $\frac{d y}{d x}$ at $t=\frac{3 \pi}{4}$ is
A
$-1$
B
$\frac{1}{\sqrt{3}}$
C
$-\sqrt{3}$
D
$1$

Solution

(D) Given $y=a \sin ^3 t$ and $x=a \cos ^3 t$.
First,differentiate $y$ with respect to $t$: $\frac{d y}{d t} = 3a \sin ^2 t \cos t$.
Next,differentiate $x$ with respect to $t$: $\frac{d x}{d t} = 3a \cos ^2 t (-\sin t) = -3a \cos ^2 t \sin t$.
Now,find $\frac{d y}{d x} = \frac{d y / d t}{d x / d t} = \frac{3a \sin ^2 t \cos t}{-3a \cos ^2 t \sin t} = -\frac{\sin t}{\cos t} = -\tan t$.
At $t = \frac{3 \pi}{4}$,$\frac{d y}{d x} = -\tan(\frac{3 \pi}{4}) = -(-1) = 1$.
40
MathematicsEasyMCQKCET · 2025
The derivative of $\sin x$ with respect to $\log x$ is
A
$\cos x$
B
$x \cos x$
C
$\frac{\cos x}{\log x}$
D
$\frac{\cos x}{x}$

Solution

(B) Let $u = \sin x$ and $v = \log x$.
We need to find the derivative of $u$ with respect to $v$,which is $\frac{du}{dv}$.
Using the chain rule,we have $\frac{du}{dv} = \frac{du/dx}{dv/dx}$.
First,find the derivative of $u$ with respect to $x$: $\frac{du}{dx} = \frac{d}{dx}(\sin x) = \cos x$.
Next,find the derivative of $v$ with respect to $x$: $\frac{dv}{dx} = \frac{d}{dx}(\log x) = \frac{1}{x}$.
Now,substitute these into the formula: $\frac{du}{dv} = \frac{\cos x}{1/x} = x \cos x$.
41
MathematicsEasyMCQKCET · 2025
The function $f(x) = \tan x - x$ is:
A
always increasing
B
always decreasing
C
never increasing
D
neither increasing nor decreasing

Solution

(A) Given the function $f(x) = \tan x - x$.
To determine the nature of the function,we find its derivative with respect to $x$:
$f'(x) = \frac{d}{dx}(\tan x - x) = \sec^2 x - 1$.
Using the trigonometric identity $1 + \tan^2 x = \sec^2 x$,we have $\sec^2 x - 1 = \tan^2 x$.
Thus,$f'(x) = \tan^2 x$.
Since the square of any real number is always non-negative,$\tan^2 x \geq 0$ for all $x$ in the domain.
Therefore,$f'(x) \geq 0$,which implies that the function $f(x)$ is always increasing.
42
MathematicsMediumMCQKCET · 2025
$\int \frac{dx}{x^2(x^4+1)^{3/4}}$ equals
A
$\left(\frac{x^4+1}{x^4}\right)^{1/4}+c$
B
$\left(x^4+1\right)^{1/4}+c$
C
$-\left(x^4+1\right)^{1/4}+c$
D
$-\left(\frac{x^4+1}{x^4}\right)^{1/4}+c$

Solution

(D) Let $I = \int \frac{dx}{x^2(x^4+1)^{3/4}}$.
Take $x^4$ common from the bracket: $I = \int \frac{dx}{x^2 \cdot (x^4)^{3/4} (1 + \frac{1}{x^4})^{3/4}} = \int \frac{dx}{x^2 \cdot x^3 (1 + \frac{1}{x^4})^{3/4}} = \int \frac{dx}{x^5 (1 + \frac{1}{x^4})^{3/4}}$.
Let $t = 1 + \frac{1}{x^4} = 1 + x^{-4}$.
Then $dt = -4x^{-5} dx$,which implies $x^{-5} dx = -\frac{1}{4} dt$.
Substituting these into the integral:
$I = \int (1 + x^{-4})^{-3/4} (x^{-5} dx) = \int t^{-3/4} \left(-\frac{1}{4} dt\right) = -\frac{1}{4} \int t^{-3/4} dt$.
Integrating with respect to $t$:
$I = -\frac{1}{4} \left(\frac{t^{1/4}}{1/4}\right) + c = -t^{1/4} + c$.
Substituting back $t = 1 + \frac{1}{x^4} = \frac{x^4+1}{x^4}$:
$I = -\left(\frac{x^4+1}{x^4}\right)^{1/4} + c$.
43
MathematicsEasyMCQKCET · 2025
The value of $\int \frac{dx}{(x+1)(x+2)}$ is
A
$\log \left|\frac{x+1}{x+2}\right|+c$
B
$\log \left|\frac{x+2}{x+1}\right|+c$
C
$\log \left|\frac{x-1}{x+2}\right|+c$
D
$\log \left|\frac{x-1}{x-2}\right|+c$

Solution

(A) To evaluate the integral $\int \frac{dx}{(x+1)(x+2)}$,we use partial fractions.
We can write the integrand as:
$\frac{1}{(x+1)(x+2)} = \frac{A}{x+1} + \frac{B}{x+2}$
$1 = A(x+2) + B(x+1)$
Setting $x = -1$,we get $A = 1$.
Setting $x = -2$,we get $B = -1$.
Thus,$\frac{1}{(x+1)(x+2)} = \frac{1}{x+1} - \frac{1}{x+2}$.
Integrating both sides:
$\int \left( \frac{1}{x+1} - \frac{1}{x+2} \right) dx = \int \frac{1}{x+1} dx - \int \frac{1}{x+2} dx$
$= \log |x+1| - \log |x+2| + c$
$= \log \left| \frac{x+1}{x+2} \right| + c$
44
MathematicsEasyMCQKCET · 2025
The value of $\int_{-1}^1 \sin^5 x \cos^4 x \, dx$ is
A
$-\pi / 2$
B
$\pi$
C
$\pi / 2$
D
$0$

Solution

(D) Let $f(x) = \sin^5 x \cos^4 x$.
We check if the function is even or odd by evaluating $f(-x)$.
$f(-x) = \sin^5(-x) \cos^4(-x) = (-\sin x)^5 (\cos x)^4 = -\sin^5 x \cos^4 x = -f(x)$.
Since $f(-x) = -f(x)$,the function $f(x)$ is an odd function.
According to the property of definite integrals,if $f(x)$ is an odd function,then $\int_{-a}^a f(x) \, dx = 0$.
Therefore,$\int_{-1}^1 \sin^5 x \cos^4 x \, dx = 0$.
45
MathematicsMediumMCQKCET · 2025
The value of $\int_0^{2 \pi} \sqrt{1+\sin \left(\frac{x}{2}\right)} d x$ is
A
$8$
B
$4$
C
$2$
D
$0$

Solution

(A) We know that $1 + \sin \theta = \cos^2 \frac{\theta}{2} + \sin^2 \frac{\theta}{2} + 2 \sin \frac{\theta}{2} \cos \frac{\theta}{2} = (\cos \frac{\theta}{2} + \sin \frac{\theta}{2})^2$.
Substituting $\theta = \frac{x}{2}$,we get $\sqrt{1 + \sin \frac{x}{2}} = |\cos \frac{x}{4} + \sin \frac{x}{4}|$.
Since $x \in [0, 2\pi]$,$\frac{x}{4} \in [0, \frac{\pi}{2}]$,where both $\sin \frac{x}{4}$ and $\cos \frac{x}{4}$ are positive.
Thus,the integral becomes $\int_0^{2\pi} (\cos \frac{x}{4} + \sin \frac{x}{4}) dx$.
Evaluating the integral: $[4 \sin \frac{x}{4} - 4 \cos \frac{x}{4}]_0^{2\pi}$.
$= (4 \sin \frac{\pi}{2} - 4 \cos \frac{\pi}{2}) - (4 \sin 0 - 4 \cos 0)$.
$= (4(1) - 4(0)) - (4(0) - 4(1)) = 4 - (-4) = 8$.
46
MathematicsMediumMCQKCET · 2025
$\int_0^1 \log \left(\frac{1}{x}-1\right) d x$ is
A
$1$
B
$0$
C
$\log _2 2$
D
$\log _e\left(\frac{1}{2}\right)$

Solution

(B) Let $I = \int_0^1 \log \left(\frac{1-x}{x}\right) d x$.
Using the property $\int_0^a f(x) d x = \int_0^a f(a-x) d x$,we get:
$I = \int_0^1 \log \left(\frac{1-(1-x)}{1-x}\right) d x$
$I = \int_0^1 \log \left(\frac{x}{1-x}\right) d x$
Adding the two expressions for $I$:
$2I = \int_0^1 \left[ \log \left(\frac{1-x}{x}\right) + \log \left(\frac{x}{1-x}\right) \right] d x$
$2I = \int_0^1 \log \left( \frac{1-x}{x} \times \frac{x}{1-x} \right) d x$
$2I = \int_0^1 \log(1) d x$
Since $\log(1) = 0$,we have $2I = 0$,which implies $I = 0$.
47
MathematicsEasyMCQKCET · 2025
The area bounded by the curve $y=\sin \left(\frac{x}{3}\right)$,the $x$-axis,and the lines $x=0$ and $x=3 \pi$ is
A
$9 \text{ sq. units}$
B
$\frac{1}{3} \text{ sq. units}$
C
$6 \text{ sq. units}$
D
$3 \text{ sq. units}$

Solution

(C) The area $A$ is given by the definite integral of the function $y = \sin \left(\frac{x}{3}\right)$ from $x = 0$ to $x = 3\pi$.
$A = \int_0^{3 \pi} \sin \left(\frac{x}{3}\right) dx$
We know that the integral of $\sin(kx)$ is $-\frac{1}{k} \cos(kx)$. Here $k = \frac{1}{3}$,so the integral is $-3 \cos \left(\frac{x}{3}\right)$.
$A = \left[ -3 \cos \left(\frac{x}{3}\right) \right]_0^{3 \pi}$
$A = -3 \left[ \cos \left(\frac{3 \pi}{3}\right) - \cos \left(\frac{0}{3}\right) \right]$
$A = -3 [ \cos(\pi) - \cos(0) ]$
Since $\cos(\pi) = -1$ and $\cos(0) = 1$:
$A = -3 [ -1 - 1 ] = -3 [ -2 ] = 6 \text{ sq. units}$.
Solution diagram
48
MathematicsEasyMCQKCET · 2025
The area of the region bounded by the curve $y=x^2$ and the line $y=16$ is
A
$\frac{32}{3}$ sq. units
B
$\frac{256}{3}$ sq. units
C
$\frac{64}{3}$ sq. units
D
$\frac{128}{3}$ sq. units

Solution

(B) The curve is $y=x^2$ and the line is $y=16$. The intersection points are found by setting $x^2=16$,which gives $x = \pm 4$.
Since the region is symmetric about the $y$-axis,the area $A$ is given by:
$A = 2 \int_0^{16} x \, dy = 2 \int_0^{16} \sqrt{y} \, dy$
$A = 2 \left[ \frac{y^{3/2}}{3/2} \right]_0^{16}$
$A = 2 \times \frac{2}{3} \left[ y^{3/2} \right]_0^{16}$
$A = \frac{4}{3} \left( 16^{3/2} - 0^{3/2} \right)$
$A = \frac{4}{3} \times (4^2)^{3/2} = \frac{4}{3} \times 4^3$
$A = \frac{4}{3} \times 64 = \frac{256}{3} \text{ sq. units}$
Solution diagram
49
MathematicsEasyMCQKCET · 2025
If $a$ and $b$ are the order and degree respectively of the differential equation $\left(\frac{d^2 y}{d x^2}\right)^2+\left(\frac{d y}{d x}\right)^3+x^4=0$,then $a-b=$
A
$1$
B
$2$
C
$-1$
D
$0$

Solution

(D) The given differential equation is $\left(\frac{d^2 y}{d x^2}\right)^2+\left(\frac{d y}{d x}\right)^3+x^4=0$.
The order of a differential equation is the order of the highest derivative present in the equation. Here,the highest derivative is $\frac{d^2 y}{d x^2}$,so the order $a = 2$.
The degree of a differential equation is the power of the highest derivative when the equation is expressed as a polynomial in derivatives. Here,the power of the highest derivative $\frac{d^2 y}{d x^2}$ is $2$,so the degree $b = 2$.
Therefore,$a - b = 2 - 2 = 0$.
50
MathematicsMediumMCQKCET · 2025
General solution of the differential equation $\frac{dy}{dx} + y \tan x = \sec x$ is
A
$y \sec x = \tan x + c$
B
$y \tan x = \sec x + c$
C
$\operatorname{cosec} x = y \tan x + c$
D
$x \sec x = \tan y + c$

Solution

(A) The given differential equation is a linear differential equation of the form $\frac{dy}{dx} + Py = Q$,where $P = \tan x$ and $Q = \sec x$.
First,we find the Integrating Factor ($I$.$F$.):
$I.F. = e^{\int P dx} = e^{\int \tan x dx} = e^{\ln |\sec x|} = \sec x$.
The general solution is given by $y \cdot (I.F.) = \int Q \cdot (I.F.) dx + c$.
Substituting the values:
$y \cdot \sec x = \int \sec x \cdot \sec x dx + c$
$y \sec x = \int \sec^2 x dx + c$
$y \sec x = \tan x + c$.
51
MathematicsEasyMCQKCET · 2025
If $\vec{a}=\hat{i}+2\hat{j}+\hat{k}$,$\vec{b}=\hat{i}-\hat{j}+4\hat{k}$,and $\vec{c}=\hat{i}+\hat{j}+\hat{k}$ are such that $\vec{a}+\lambda\vec{b}$ is perpendicular to $\vec{c}$,then the value of $\lambda$ is
A
$1$
B
$\pm 1$
C
$-1$
D
$0$

Solution

(C) Given vectors are $\vec{a} = \hat{i} + 2\hat{j} + \hat{k}$,$\vec{b} = \hat{i} - \hat{j} + 4\hat{k}$,and $\vec{c} = \hat{i} + \hat{j} + \hat{k}$.
Since $\vec{a} + \lambda\vec{b}$ is perpendicular to $\vec{c}$,their dot product must be zero:
$(\vec{a} + \lambda\vec{b}) \cdot \vec{c} = 0$
First,calculate $\vec{a} + \lambda\vec{b}$:
$\vec{a} + \lambda\vec{b} = (\hat{i} + 2\hat{j} + \hat{k}) + \lambda(\hat{i} - \hat{j} + 4\hat{k}) = (1 + \lambda)\hat{i} + (2 - \lambda)\hat{j} + (1 + 4\lambda)\hat{k}$
Now,take the dot product with $\vec{c} = \hat{i} + \hat{j} + \hat{k}$:
$((1 + \lambda)\hat{i} + (2 - \lambda)\hat{j} + (1 + 4\lambda)\hat{k}) \cdot (\hat{i} + \hat{j} + \hat{k}) = 0$
$(1 + \lambda)(1) + (2 - \lambda)(1) + (1 + 4\lambda)(1) = 0$
$1 + \lambda + 2 - \lambda + 1 + 4\lambda = 0$
$4 + 4\lambda = 0$
$4\lambda = -4$
$\lambda = -1$
52
MathematicsEasyMCQKCET · 2025
If $|\vec{a}|=10, |\vec{b}|=2$ and $\vec{a} \cdot \vec{b}=12$,then the value of $|\vec{a} \times \vec{b}|$ is
A
$5$
B
$10$
C
$14$
D
$16$

Solution

(D) We know that $\vec{a} \cdot \vec{b} = |\vec{a}| |\vec{b}| \cos \theta$.
Substituting the given values: $12 = 10 \times 2 \times \cos \theta$.
$12 = 20 \cos \theta \implies \cos \theta = \frac{12}{20} = \frac{3}{5}$.
Since $\sin^2 \theta + \cos^2 \theta = 1$,we have $\sin \theta = \sqrt{1 - (\frac{3}{5})^2} = \sqrt{1 - \frac{9}{25}} = \sqrt{\frac{16}{25}} = \frac{4}{5}$.
Now,$|\vec{a} \times \vec{b}| = |\vec{a}| |\vec{b}| \sin \theta$.
$|\vec{a} \times \vec{b}| = 10 \times 2 \times \frac{4}{5} = 20 \times \frac{4}{5} = 16$.
53
MathematicsEasyMCQKCET · 2025
Consider the following statements :
Statement $(I)$ : If either $|\vec{a}|=0$ or $|\vec{b}|=0$,then $\vec{a} \cdot \vec{b}=0$.
Statement $(II)$ : If $\vec{a} \times \vec{b}=\vec{0}$,then $\vec{a}$ is perpendicular to $\vec{b}$.
Which of the following is correct?
A
Statement $(I)$ is false but Statement $(II)$ is false
B
Statement $(I)$ is false but Statement $(II)$ is true
C
Both Statement $(I)$ and Statement $(II)$ are true
D
Both Statement $(I)$ and Statement $(II)$ are false

Solution

(A) Statement $(I)$ : The dot product of two vectors $\vec{a}$ and $\vec{b}$ is defined as $\vec{a} \cdot \vec{b} = |\vec{a}| |\vec{b}| \cos \theta$. If $|\vec{a}|=0$ or $|\vec{b}|=0$,then $\vec{a} \cdot \vec{b} = 0 \times |\vec{b}| \cos \theta = 0$ or $\vec{a} \cdot \vec{b} = |\vec{a}| \times 0 \times \cos \theta = 0$. Thus,Statement $(I)$ is true.
Statement $(II)$ : The cross product of two vectors is defined as $\vec{a} \times \vec{b} = |\vec{a}| |\vec{b}| \sin \theta \hat{n}$. If $\vec{a} \times \vec{b} = \vec{0}$,then $\sin \theta = 0$,which implies $\theta = 0$ or $\theta = \pi$. This means the vectors are parallel or collinear,not perpendicular. Thus,Statement $(II)$ is false.
54
MathematicsEasyMCQKCET · 2025
If a line makes angles $90^{\circ}, 60^{\circ}$ and $\theta$ with $x, y$ and $z$ axes respectively,where $\theta$ is acute,then the value of $\theta$ is
A
$\frac{\pi}{6}$
B
$\frac{\pi}{4}$
C
$\frac{\pi}{3}$
D
$\frac{\pi}{2}$

Solution

(A) The direction cosines of a line are given by $\cos \alpha, \cos \beta, \cos \gamma$,where $\alpha, \beta, \gamma$ are the angles made with the $x, y, z$ axes respectively.
Here,$\alpha = 90^{\circ}, \beta = 60^{\circ}, \gamma = \theta$.
The sum of the squares of the direction cosines is always $1$,so $\cos^2 \alpha + \cos^2 \beta + \cos^2 \gamma = 1$.
Substituting the values: $\cos^2 90^{\circ} + \cos^2 60^{\circ} + \cos^2 \theta = 1$.
$(0)^2 + (\frac{1}{2})^2 + \cos^2 \theta = 1$.
$0 + \frac{1}{4} + \cos^2 \theta = 1$.
$\cos^2 \theta = 1 - \frac{1}{4} = \frac{3}{4}$.
Since $\theta$ is acute,$\cos \theta = \frac{\sqrt{3}}{2}$.
Therefore,$\theta = 30^{\circ}$ or $\frac{\pi}{6}$ radians.
55
MathematicsMediumMCQKCET · 2025
The equation of the line passing through the point $(0,1,2)$ and perpendicular to the line $\frac{x-1}{2}=\frac{y+1}{3}=\frac{z-1}{-2}$ is
A
$\frac{x}{3}=\frac{y-1}{4}=\frac{z-2}{-3}$
B
$\frac{x}{-3}=\frac{y-1}{4}=\frac{z-2}{3}$
C
$\frac{x}{3}=\frac{y-1}{4}=\frac{z-2}{3}$
D
$\frac{x}{3}=\frac{y-1}{-4}=\frac{z-2}{3}$

Solution

(B) Let the required line pass through the point $P(0,1,2)$ with direction ratios $(a, b, c)$.
The equation of the line is $\frac{x-0}{a} = \frac{y-1}{b} = \frac{z-2}{c}$.
The given line is $\frac{x-1}{2} = \frac{y+1}{3} = \frac{z-1}{-2}$,which has direction ratios $(2, 3, -2)$.
Since the two lines are perpendicular,the dot product of their direction ratios must be zero:
$2a + 3b - 2c = 0$.
Checking the options:
For option $C$: The direction ratios are $(3, 4, 3)$.
$2(3) + 3(4) - 2(3) = 6 + 12 - 6 = 12 \neq 0$.
For option $B$: The direction ratios are $(-3, 4, 3)$.
$2(-3) + 3(4) - 2(3) = -6 + 12 - 6 = 0$.
Thus,the line $\frac{x}{-3} = \frac{y-1}{4} = \frac{z-2}{3}$ is perpendicular to the given line.
56
MathematicsEasyMCQKCET · 2025
Consider the following statements:
Statement $(I)$: In a $LPP$,the objective function is always linear.
Statement $(II)$: In a $LPP$,the linear inequalities on variables are called constraints.
Which of the following is correct?
A
Statement $(I)$ is true,Statement $(II)$ is true
B
Statement $(I)$ is true,Statement $(II)$ is false
C
Both Statements $(I)$ and $(II)$ are false
D
Statement $(I)$ is false,Statement $(II)$ is true

Solution

(A) Both Statement $(I)$ and Statement $(II)$ are true in a Linear Programming Problem $(LPP)$:
Statement $(I)$:
The objective function in an $LPP$ is always linear,meaning it can be expressed as a linear equation with the variables raised to the power of $1$.
Statement $(II)$:
The linear inequalities that restrict the variables in an $LPP$ are called constraints.
Explanation:
In a linear programming problem,you are trying to optimize (maximize or minimize) an objective function (a linear equation) while adhering to certain constraints (linear inequalities) that limit the possible values of the variables.
57
MathematicsMediumMCQKCET · 2025
The maximum value of $z=3x+4y$,subject to the constraints $x+y \leq 40$,$x+2y \leq 60$ and $x, y \geq 0$ is
A
$130$
B
$120$
C
$140$
D
$40$

Solution

(C) To find the maximum value of the objective function $z=3x+4y$,we identify the feasible region defined by the constraints:
$1$. $x+y \leq 40$
$2$. $x+2y \leq 60$
$3$. $x, y \geq 0$
The corner points of the feasible region are determined by the intersection of these lines and the axes:
- Intersection of $x+y=40$ and $x+2y=60$: Subtracting the first from the second gives $y=20$,which implies $x=20$. Point: $(20, 20)$.
- Intersection of $x+y=40$ with the $x$-axis $(y=0)$: Point $(40, 0)$.
- Intersection of $x+2y=60$ with the $y$-axis $(x=0)$: Point $(0, 30)$.
- The origin $(0, 0)$ is also a corner point.
Now,evaluate $z=3x+4y$ at each corner point:
- At $(0, 0)$: $z = 3(0) + 4(0) = 0$
- At $(40, 0)$: $z = 3(40) + 4(0) = 120$
- At $(0, 30)$: $z = 3(0) + 4(30) = 120$
- At $(20, 20)$: $z = 3(20) + 4(20) = 60 + 80 = 140$
The maximum value is $140$ at the point $(20, 20)$.
Solution diagram
58
MathematicsEasyMCQKCET · 2025
If $A$ and $B$ are two non-mutually exclusive events such that $P(A \mid B) = P(B \mid A)$,then
A
$A \subset B$ but $A \neq B$
B
$A = B$
C
$A \cap B = \phi$
D
$P(A) = P(B)$

Solution

(D) Given that $A$ and $B$ are non-mutually exclusive events,we have $P(A \cap B) \neq 0$.
Given the condition $P(A \mid B) = P(B \mid A)$.
Using the definition of conditional probability,we have:
$\frac{P(A \cap B)}{P(B)} = \frac{P(B \cap A)}{P(A)}$
Since $P(A \cap B) = P(B \cap A)$,we can divide both sides by $P(A \cap B)$ because $P(A \cap B) \neq 0$:
$\frac{1}{P(B)} = \frac{1}{P(A)}$
Therefore,$P(A) = P(B)$.
59
MathematicsMediumMCQKCET · 2025
Consider the following statements.
Statement $(I)$: If $E$ and $F$ are two independent events,then $E^{\prime}$ and $F^{\prime}$ are also independent.
Statement $(II)$: Two mutually exclusive events with non-zero probabilities of occurrence cannot be independent.
Which of the following is correct?
A
Statement $(I)$ is true and statement $(II)$ is false
B
Statement $(I)$ is false and statement $(II)$ is true
C
Both the statements are true
D
Both the statements are false

Solution

(C) Statement $(I)$: If $E$ and $F$ are independent,then $P(E \cap F) = P(E)P(F)$. We know that $P(E^{\prime} \cap F^{\prime}) = P((E \cup F)^{\prime}) = 1 - P(E \cup F) = 1 - [P(E) + P(F) - P(E \cap F)] = 1 - P(E) - P(F) + P(E)P(F) = (1 - P(E))(1 - P(F)) = P(E^{\prime})P(F^{\prime})$. Thus,$E^{\prime}$ and $F^{\prime}$ are independent. Statement $(I)$ is true.
Statement $(II)$: If $E$ and $F$ are mutually exclusive,then $P(E \cap F) = 0$. For them to be independent,we require $P(E \cap F) = P(E)P(F)$. Since $P(E) > 0$ and $P(F) > 0$,$P(E)P(F) > 0$. Thus,$P(E \cap F) \neq P(E)P(F)$,meaning they cannot be independent. Statement $(II)$ is true.
60
MathematicsMediumMCQKCET · 2025
Meera visits only one of the two temples $A$ and $B$ in her locality. The probability that she visits temple $A$ is $\frac{2}{5}$. If she visits temple $A$,the probability that she meets her friend is $\frac{1}{3}$,whereas it is $\frac{2}{7}$ if she visits temple $B$. Meera met her friend at one of the two temples. The probability that she met her at temple $B$ is
A
$\frac{7}{16}$
B
$\frac{5}{16}$
C
$\frac{3}{16}$
D
$\frac{9}{16}$

Solution

(D) Let $A$ be the event that Meera visits temple $A$ and $B$ be the event that she visits temple $B$. Let $F$ be the event that she meets her friend.
Given:
$P(A) = \frac{2}{5}$
$P(B) = 1 - P(A) = 1 - \frac{2}{5} = \frac{3}{5}$
$P(F|A) = \frac{1}{3}$
$P(F|B) = \frac{2}{7}$
We need to find the probability that she met her friend at temple $B$,which is $P(B|F)$.
Using Bayes' Theorem:
$P(B|F) = \frac{P(B) \times P(F|B)}{P(A) \times P(F|A) + P(B) \times P(F|B)}$
$P(B|F) = \frac{\frac{3}{5} \times \frac{2}{7}}{(\frac{2}{5} \times \frac{1}{3}) + (\frac{3}{5} \times \frac{2}{7})}$
$P(B|F) = \frac{\frac{6}{35}}{\frac{2}{15} + \frac{6}{35}}$
Finding a common denominator for the denominator: $15 = 3 \times 5$ and $35 = 7 \times 5$,so $LCM$ is $105$.
$P(B|F) = \frac{\frac{6}{35}}{\frac{14}{105} + \frac{18}{105}} = \frac{\frac{18}{105}}{\frac{14+18}{105}} = \frac{18}{32} = \frac{9}{16}$

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