`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`

sin^(2)A cos^(2)B-cos^(2)A sin^(2)B=sin^(2)A-sin^(2)B

sin^(2) A cos^(2)B + cos ^(2) A sin^(2) B + sin^(2) A sin^(2) B+ cos^(2) A cos^(2) B=

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

The value of sin^2 A cos^2 B + cos^2 A cos^2 B+sin^2 A sin^2 B + cos^2A sin^2B is ……..

Prove the following tan^2A- tan^ 2B=(sin^2A-sin^2B)/(cos^2A*cos^2B) =(cos^2B-cos^2A) /(cos^2A*cos^2B)

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

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

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

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

If (cos^4A)/(cos^2B)+(sin^4A)/(sin^2B)=1 then prove that (i)sin^4A+sin^4B=2sin^2Asin^2B (ii)(cos^4B)/(cos^2A)+(sin^4B)/(sin^2A)=1