#1: It often helps to rewrite it in terms to sine and cosine.
I'm completely stumped. were supposed to prove the equations true. if you could help me that would be great!
3.) sec^2(θ)-sec^2(θ)sin^2(θ)=1
4.) sec^2(θ)cot^2(θ)-1=cot^2(θ)
5.) 1/sec(θ)-cos(θ)=cot(θ)csc(θ)
6.) sec^2(θ)+csc^2(θ)=csc^2(θ)sec^2(θ)
7.) [1/sin(θ)+1] - [1/sin(θ)-1]=2sec^2(θ)
8.) [sin(θ)tan(θ]/[1-cos(θ)]=sec(θ)=1