Question

Let the function f(x) have the form f(x) = Acos(x-C). To produce a graph that matches the one shown below, what must the value of C be?

Answer 1

Answer: Option B, C = 3.

Explanation:

Here we have the function:

f(x) = A*cos(x - C)

A is the amplitude, and we can easily see that the amplitude is 2.

Then:

f(x) = 2*cos(x - C)

We also can see that when x = 0, f(x) ≈ -2

This means that:

cos(0 - C) ≈ -1

Cos(C) ≈ -1

Now we can just evaluate in the different options and see which one is the correct option.

Cos(1) = 0.54

Cos(2) = -0.42

Cos(3) = -0.99

Cos(4) = -0.65

The closer option to -1 is when C = 3, then the correct option is option B.