This document discusses solving trigonometric equations and finding trigonometric ratios given specific conditions. It provides examples of finding sin θ when cos 2θ = -1 and θ is between 180° and 360°, and finding sec θ when tan θ = -1 and θ is between quadrants. It also gives the solution set for sin θ = 1/2 over the reals between 0 and 2π.