[" Ficg oxt "widehat Q" ."],[" 9."cos(A+B)cos(A-B)=cos^(2)A-sin^(2)B]

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

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

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

If A+B+C = pi , show that |["sin"^(2)A, "sin A cos A", "cos"^(2)A],["sin"^(2) B, "sin B cos B", "cos"^(2)B],["sin"^(2)C, "sin C cos C", "cos"^(2)C]| =-"sin (A-B)"sin"(B-C)"sin"(C-A)"

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

If (cos A)/(cos B)=p,(sin A)/(sin B)=q ,then (p^(2)(q^(2)-1))/(p^(2)-q^(2)) is equal to (A)-cos^(2)A(B)cos^(2)B(C)cos^(2)A(D)sin^(2)B

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

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

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