Solve each equation for exact solutions over the interval [0,360)where appropriate. Round approximate solutions to the nearest tenth degree. Sin^2Theta=Cos^2Theta+1

Question

My Work: Using double angle Identity I subtract 1 to other side therefore:
1-Sin^2theta=Cos^2theta= Cos2theta=Cos^2theta.

This is where I am stuck.For this does not conclude an answer...

Answer 1

since sin^2θ is never more than 1, you need cos^2θ = 0

so, θ = π/2 or 3π/2

or, solving algebraically,

sin^2θ = cos^2θ + 1
cos^2θ - sin^2θ = -1
cos(2θ) = -1
θ = π/2 or 3π/2

Answer 2

2sintheta-1=cscthet