If $a+ib = \frac{(x+i)^{2}}{2x^{2}+1}$,prove that $a^{2}+b^{2} = \frac{(x^{2}+1)^{2}}{(2x^{2}+1)^{2}}$.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) Given $a+ib = \frac{(x+i)^{2}}{2x^{2}+1}$.
Expanding the numerator using $(A+B)^{2} = A^{2}+B^{2}+2AB$:
$a+ib = \frac{x^{2}+i^{2}+2xi}{2x^{2}+1}$
Since $i^{2} = -1$:
$a+ib = \frac{x^{2}-1+i(2x)}{2x^{2}+1}$
Separating the real and imaginary parts:
$a+ib = \frac{x^{2}-1}{2x^{2}+1} + i\left(\frac{2x}{2x^{2}+1}\right)$
Comparing real and imaginary parts:
$a = \frac{x^{2}-1}{2x^{2}+1}$ and $b = \frac{2x}{2x^{2}+1}$
Now,calculate $a^{2}+b^{2}$:
$a^{2}+b^{2} = \left(\frac{x^{2}-1}{2x^{2}+1}\right)^{2} + \left(\frac{2x}{2x^{2}+1}\right)^{2}$
$= \frac{(x^{2}-1)^{2} + (2x)^{2}}{(2x^{2}+1)^{2}}$
$= \frac{x^{4}+1-2x^{2}+4x^{2}}{(2x^{2}+1)^{2}}$
$= \frac{x^{4}+2x^{2}+1}{(2x^{2}+1)^{2}}$
$= \frac{(x^{2}+1)^{2}}{(2x^{2}+1)^{2}}$
Thus,$a^{2}+b^{2} = \frac{(x^{2}+1)^{2}}{(2x^{2}+1)^{2}}$. Hence,proved.

Explore More

Similar Questions

If $n$ is a positive integer and $\frac{(1+i)^n}{(1-i)^n} = -i$,then $n$ will be of the form:

If $\left|\begin{array}{cc}1-i & i \\ 1+2 i & -i\end{array}\right|=x+i y$,then $x$ is equal to

Express the given complex number in the form $a+ib$: $(1-i)^{4}$

If $\left(\frac{1-i}{1+i}\right)^{100}=a+ib$,where $a, b \in \mathbb{R}$ and $i=\sqrt{-1}$,then $(a, b)$ is equal to

Let $\left(-2-\frac{1}{3} i\right)^3=\frac{x+i y}{27}$,where $i=\sqrt{-1}$ and $x, y$ are real numbers. Then the value of $(y-x)$ is:

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo