Identify the maximum and minimum values of the function y = 10 cos x in the interval [-2π ,2π]. use your understanding of transformations, not your graphing calculator. (3 points)

The period of the cosine function is 2π, so the interval represents two full periods of the function. Within a period, the maximum is 1 and the minimum is -1.

The given function scales the cosine function vertically by a facor of 10. This tells you the transformed function will have a ...
  maximum of 10×(1) = 10
  minimum of 10×(-1) = -10
on the given interval.

The range of the function is (in other words ). Then that means that the range of the function is .

The minimal value is when 
.

The maximal value is when
 .