" 5."(cos2R+sin2A)/(cos2b-cos2/1)=cot(A+B)cot(1-B)

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

Prove that: (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))

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

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

prove that (sin2A)/(1-cos2A)=cot A

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

Prove: cot^(2)A cos ec^(2)B-cot^(2)B cos ec^(2)A=cot^(2)A-cot^(2)B

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