Prove that ` sin (A+B)= sin A cos B + cos A sin B. `

Prove that sin(A+B+C)=sin A cos B cos C+cos A sin B cos C+cos A cos B sin C-sin A sin B sin Ccos(A+B+C)=cos A cos B cos C-cos A sin B sin C-sin A cos B sin C-sin A sin B cos C

Prove that : cos (A + B) = cos A cos B - sin A sin B .

Prove that : cos (A - B) = cos A cos B + sin A sin B .

Prove by vector method that sin(A-B)=sin A cos B-cos A sin B and sin(A+B)=sin A cos B+cos A sin B

Prove that cos (A + B) cos C - cos (B + C) cos A = sin B sin (C - A)

For any A,B in R, prove that cos(A-B)=cos A cos B+sin A sin B

Prove that : (sin A - sin B)/ (cos A + cos B) + (cos A - cos B)/ (sin A + sin B) = 0

Prove that (1 + sin A) / (cos A) + (cos B) / (1-sin B) = (2sin A-2sin B) / (sin (AB) + cos A-cos B)

Prove that sin (A+B) sin (A-B)=cos^(2) B-cos^(2) A

In any DeltaABC , prove that : a cos A + b cos B + c cos C = 2a sin B sin C