I have a question to ask, would anyone of you explain to me how to solve this?

1. Prove that (1+cosθ+sin2θ)/(1-cos2θ+sin2θ)=cotθ

I'm able to prove it but,,

Then the following part asks me solve the equation for 0≤θ≤2π

1+sin2θ=3cos2θ

How would you go about doing this? I appreciate your help!