Choose the function whose graph is given by:

y = 0.5cos(x), choice A

The parent function y = cos(x) follows this same basic pattern of the curve shown, but it starts off at (0,1) as its highest point. This graph has its highest point to be half as high, so we multiply by 1/2 or 0.5

  y = 0.5·cos(x)

Step-by-step explanation:

The peak is at x=0 and is 1/2, so it is a positive cosine function with a multiplier of 1/2. The period is about 2π, so the multiplier on x is 1.

The graph matches ...

  y = 0.5·cos(x)

i just took the test, the correct answer is .. 31.5 in.