In triangle ABC,if a=13, b=8, c=7,then cos(B+ | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(D) In any triangle $ABC$,the sum of angles is $A+B+C = 180^{\circ}$.Therefore,$B+C = 180^{\circ} - A$.Thus,$\cos(B+C) = \cos(180^{\circ} - A) = -\cos

Vedclass · Accepted Answer

$\frac{1}{2}$

Vedclass · Answer

(D) In any triangle $ABC$,the sum of angles is $A+B+C = 180^{\circ}$.Therefore,$B+C = 180^{\circ} - A$.Thus,$\cos(B+C) = \cos(180^{\circ} - A) = -\cos A$.Using the Law of Cosines,$\cos A = \frac{b^2 + c^2 - a^2}{2bc}$.Substituting the given values $a=13, b=8, c=7$:$\cos A = \frac{8^2 + 7^2 - 13^2}{2 	imes 8 	imes 7} = \frac{64 + 49 - 169}{112} = \frac{113 - 169}{112} = \frac{-56}{112} = -\frac{1}{2}$.Finally,$\cos(B+C) = -\cos A = -(-\frac{1}{2}) = \frac{1}{2}$.

In triangle $ABC$,if $a=13, b=8, c=7$,then $\cos(B+C) = $

Similar Questions

In a triangle $ABC$,if $2a^2b^2 + 2b^2c^2 = a^4 + b^4 + c^4$,then angle $B$ is equal to:

If in a $\triangle ABC$,$r_1 < r_2 < r_3$,then:

If $b+c=3a$,then $\cot \frac{B}{2} \cot \frac{C}{2}$ is equal to :

The smallest angle of the $\Delta ABC$,when $a = 7, b = 4\sqrt{3}$ and $c = \sqrt{13}$,is .....$^o$

If $a = 2, b = 3, c = 5$ in $\Delta ABC$,then $C = $

Vedclass Test Series

Exam Paper Generator

Online Exam Module