trigonometry

[dr brijesh kumar]

If Square root a-b/a+b=tanAtanB;show that axa-bxb=(a-bCos2A)(a-bCos2B)

 

[mmm4444bot]

What have you tried thus far?

I would square both sides of the first equation, to begin. Also, the difference-of-squares a^2 - b^2 is factorable.