सिद्ध कीजिए कि
`cos^(2) A+ cos^(2) B - 2 cos A cos B `
` 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)

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

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

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

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

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

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