Question

For what x-value(s) does cos(x) = 1?

-360°

0°

360°

all of the above

Answer 1

cos(x) = 1 at 0 and 2pi 360 and -360 is the same angle as 2pi so all of the above if you start at 0 and make a complete circle (360) you will be back at point 0.