Question

When θ = 0, cos θ = 1. What is the next radian value that will result in cos θ = 1?

Answer 1

The only place where cos = 1 is at the coordinate point (1,0) on the unit circle (when theta=0). So, if you revolve around the unit circle once more from theta=0, you get that theta =2pi since the circumference of the unit circle in radians is 2pi.