Question

Prove , tan 4 q+tan 2 q = sec 4 q-sec 2 q

Answer 1

LHS=tan^4 q+tan²q
LHS=tan²q(tan²q+1)
LHS=(tan²q)(sec²q)                           [∵tan²q+1=sec²q]
LHS=(sec²q-1)sec²q
LHS=sec^4 q-sec²q
LHS=RHS
    hence proved