(cos2B+cos2A)/(cos2B-cos2A)=

(cos2B-cos2A)/(sin2B+sin2A)=tan(AB)

Prove the following tan^2A- tan^ 2B=(sin^2A-sin^2B)/(cos^2A*cos^2B) =(cos^2B-cos^2A) /(cos^2A*cos^2B)

Prove the following identities: tan^(2)A-tan^(2)B=(cos^(2)B-cos^(2)A)/(cos^(2)B cos^(2)A)=(sin^(2)A-sin^(2)B)/(cos^(2)A cos^(2)B)(sin A-sin B)/(cos A+cos B)+(cos A-cos B)/(sin A+sin B)=0

If A+B+C = (3pi)/(2),then cos2A+cos2B+cos2C=

If A+B+C=180^(@) , then (cos2A+cos2B+cos2C+1)/(cos A cos B cos C)

If A+B+C=180^(@) then prove that the following: cos2A+cos2B-cos2C =1-4sinAsinBcosC

In any triangle A B C , prove that following: \ (cos^2B-cos^2C)/(b+c)+(cos^2C-cos^2A)/(c+a)+(cos^2A-cos^2B)/(a+b)=0

If A+B+C=270^(@) then cos2A+cos2B+cos2C=

In any DeltaABC , prove that (cos2A)/a^(2)-(cos2B)/b^(2)=(1/a^(2)-1/b^(2))