Hi,

I am realllly bad at proving identities... so I would appreciate any advice you have, when proving these three identities:

(4/4a+4) + (7/7a-7) = (2a^2 + 2a/a^2 + 2a + 1) * (a+2)/(a^2+a-2)

also:

tan^2x/sec^2x = sin^2x

also:

(1+tan^2x)(a-sin^2x)=1

thank you for any guidance you have to offer