`cos (A+B)cos (A-B) –sin (A+B) sin (A-B) =cos 2A`

If det [[cos (A + B), - sin (A + B), cos2Bsin A, cos A, sin B-cos A, sin A, cos B]] = 0

If det [[cos (A + B), - sin (A + B), cos2Bsin A, cos A, sin B-cos A, sin A, cos B]] = 0

cos (A +B) + sin (A -B) = 2 sin (45 ^(@) + A) cos ( 45 ^(@) + B).

Prove (i)sin(A+B)+sin(A-B)=2sin A cos B (ii) sin(A+B)-sin(A-B)=2cos A sin B

sin 2A + sin 2B + sin 2 (A-B)= A) 4 sin A * sin B * sin (A-B) B) 4 sin A * cos B * cos (A-B) C) 4 cos A * sin B * cos (A-B) D) 4 cos A * cos B * sin (A-B)

cos(A+B)*cos(A-B)= (a) sin^2A-cos^2B (b) cos^2A-sin^2B (c) sin^2A-sin^2B (d) cos^2A-cos^2B

if ( cos A + cos B )/( sin A + sin B ) = k ( (sin A - sin B)/ ( cos A- cos B)) then k is

If sin (A-B)=sin A cos B-cos A sin B and cos (A - B) = cos A cos B + sin A sin B . find the values of sin 15^@ and cos 15^@.

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

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