For any angles A and B, `cos(A+B).cos(A-B)=…..`

For all values of angle A and B(i)cos(A-B)=cos A cos B+sin A sin B(ii)cos(A+B)=cos A cos B-sin A sin B

If B be the exterior angle of a regular polygon of n - sides and A is any constant then cos A + cos(A+ B)+cos(A+2B)....n terms is equal to

For any triangle ABC,prove that a cos A+b cos B+c cos C=2a sin B sin C

For all values of angle A and B(i)sin(A-B)=sin A cos B-cos A sin B(ii)sin(A+B)=sin A cos B+cos A sin B

In a triangle ABC, prove that for any angle theta,b cos(A-theta)+a cos(B+theta)=C cos theta

If B be the exterior angle of a regular polygon of n- sides and A is any constant then cos A+cos(A+B)+cos(A+2B)...n terms is equal to

In a triangle ABC, prove that for any angle theta, b cos (A - theta) + a cos (B + theta) = C cos theta .

In any triangle, (1+ cos (A-B)cos C)/(1+cos (A-C)cos B)=

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