Question
Question: In a triangle ABC, \(\frac { \cos B + \cos C } { 1 - \cos A }\)=...
In a triangle ABC, 1−cosAcosB+cosC=
A
1−ab+c
B
1−abc
C
ab+c
D

Answer
ab+c
Explanation
Solution
Q b = c cos A + a cos C , c = a cos B + b cos A
̃ b + c = (b + c) cos A + a (cos B + cos C)
̃ (b + c) (1 – cos A) = a (cos B + cos C)
̃ 1−cosAcosB+cosC = ab+c