Question: cos x is equal to?
Answer: The sine and cosine functions are said to be periodic with period 2 : sin (x + 2n ) = sin (x) and cos (x + 2n ) = cos x for any integer n. The maximum value attained by sin(x) or by cos (x) is 1, and the minimum value is -1. The functions oscillate in a regular manner within 1 unit of the x-axis (y = 0).