1) Factor the expression then use fundamental identities to simplify

1) Factor the expression then use fundamental identities to simplify

Cos^2xsec^2x-cos^2x

2) Perform the subtraction then use the fundamental identities to simplify

a)  1/secx+1 - 1/secx-1

b)  tanx- sec^2x/tanx

Really need help understanding how to do these problems?