Let A and B denote the statements A: `"cos"a+"cos"b+"cos"g=""0` B : `"sin"a+"sin"b+"sin"g=""0` If `cos(b g)""+""cos(g a)""+""cos(a b)""=""""3//2` , then (1) A is true and B is false (2) A is false and B is true (3) both A and B are true (4) both A and B are false

Let A and B denote the statements A: "cos"alpha+"cos"beta+"cos"gamma=""0 B : "sin"alpha+"sin"beta+"sin"gamma=""0 If cos(beta-gamma)""+""cos(gamma-alpha)""+""cos(alpha-beta)""=""""-(3//2) , then (1) A is true and B is false (2) A is false and B is true (3) both A and B are true (4) both A and B are false

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

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

Prove that (sin A+sin B)/(cos A+cos B)+(cos A-cos B)/(sin A-sin B)=0

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

If sin A + cos B = a and sin B + cos A = b, then sin (A + B) is equal to