# How do I solve a trig equation over an interval?

I have an equation $4\sin^2(θ) = 1+4\cos(θ)$. I need to solve this equation on the interval $0<=θ<2 π$.

How would I use the Solve and/or Reduce commands to solve this equation?

Reduce[{4 Sin[θ]^2 == 1 + 4 Cos[θ], 0 <= θ < 2 π}]

• you can use Solve as well: see the latest edit – kevin Nov 17 '16 at 6:32