If `A+B+C=180^0`, prove that : `cos^2(A/2) + cos^2(B/2) - cos^2(C/2) = 2cos(A/2) cos(B/2) sin( C/2)`
Channel: Doubtnut
Date: 2020-04-12

If `A+B+C=180^0`, prove that : `cos^2(A/2) + cos^2(B/2) - cos^2(C/2) = 2cos(A/2) cos(B/2) sin( C/2)`