[(cos^(2)A-cos^(2)B)/(sin A cos A-sin B cos B)=],[[" A) "tan(A+B)],[" () ",cot(A+B)],[" D) ",-cot(A+B)]]

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

(sin^2A- sin^2B)/( sin A cos A-sin Bcos B) = .............. A) tan (A-B) B) tan (A+B) C) cot (A-B) D) cot (A+B)

(sin^(2)A-sin^(2)B)/(sin A cos A-sin B cos B) is equal to (a) sin A cos A-sin B cos Btan(A-B)(b)tan(A+B)cot(A-B)(d)cot(A+B)

(sin A + sin B) / (cos A + cos B) = tan ((A + B) / (2))

(sin A-sin B)/(cos B-cos A)=cot((A+B)/(2))

Prove that (sin A-sin B)/(cos A+ cos B) = "tan" (A-B)/2

(cos A+cos B)/(cos B-cos A)=cot((A+B)/(2))cot((A-B)/(2))

(1-cos A+cos B-cos(A+B))/(1+cos A-cos B-cos(A+B))=(tan A)/(2)(cot B)/(2)

cot A+cot B+cot C+(cos(A+B+C))/(sin A sin B sin C)=

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