Solve:cos^2x=1 for 0 < x is less than or equal to 2pi
cos^2 x = 1
take square root of both sides
+- cos x = 1
cos x = 1
cos x = -1
for what angle value is cos = 1 and cos = -1 ?
take square root of both sides
+- cos x = 1
cos x = 1
cos x = -1
for what angle value is cos = 1 and cos = -1 ?