Question

Consider the function y = -2 - 3cos(x + pi). What effect does the 3 have?

A. Horizontal shift of y = -2 - cos(x + pi) right 3 units.
B. Vertical stretch of y = -2 - cos(x + pi) by a factor of 3.
C. Vertical shift of y = -2 - cos(x + pi) down 3 units.
D. Horizontal shift of y = -2 - cos(x + pi) left 3 units.

Answer 1

-3 would be the 'a' value.

We can rewrite that as \(\large y = - 3cos(x + pi)-2\)

-3 is the amplitude.

Answer 2

So it should be a vertical stretch, so B).