Question

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.

Answer 1

Cosine has a known range of [-1,1], so normally the max and min would be -1, and 1 respectively. Since the function is being multiplied by 10, the max and min would be 10 times that much, making the max: 10, and the min: -10.

Answer 2

maximum and minimum values of cos x in this interval is 1 and -1

and the graph is stretched by a factor of 10 parallel to y-axis

Answer 3

that, makes so much more sense than how my textbook describes it