[" cos "B" sin "(x-c)cos^(2)A+cos^(2)B-2cos A cos B],[" the chisie "],[cos(A+B)=sin^(2)(A+B)]

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

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

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

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

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

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

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

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

If : A+B+C=pi, "then" : 1-cos^(2) A-cos^(2)B-cos^(2)C= A) 2 cos A * cos B * cos C B) 2 sin A * cos B * cos C C) 2 cos A * sin B * cos C D) 2 cos A * cos B * sin C

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