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

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

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

(cos2B+cos2A)/(cos2B-cos2A)=cot(A+B)*cot(A-B)

If none of A,B, A+B is an integral multiple of pi , then prove that (1- cos A+ cos B- cos (A+B))/(1+ cos A- cos B - cos (A+B))=tan.(A)/(2) cot. (B)/(2)

In Delta ABC, show that (1-cos A+cos B+cos C)/(1-cos C+cos A+cos B)=tan((A)/(2))cot((C)/(2))

In Delta ABC, if cos A+2cos B+cos C=2 and cot((A)/(2))+cot((C)/(2))=lambda cot((B)/(2)) ,then find the value of lambda

prove that ((cos A+cos B)/(sin A-sin B))^(n)+((sin A+sin B)/(cos A-cos B))^(n)=2cot^(n)((A-B)/(2)),n is even

Prove that: ((cos A+cos B)/(sin A-sin B))^(n)+((sin A+sin B)/(cos A-cos B))^(n)={2cot^(n)((A-B)/(2)),quad if niseven0,if nisodd

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

If a,b and c be in A.P. prove that cos A cot((A)/(2)),cos B cot((B)/(2)), and cos C cot((C)/(2)) are in A.P.