Question

What is the amplitude, period, and phase shift of f(x) = −3 cos(4x + π) + 6?

Answer 1

These are the answer choices:

A: Amplitude = 3; period = pi over two; phase shift: x = negative pi over four

B: Amplitude = −3; period = pi over two; phase shift: x = pi over four

C: Amplitude = −3; period = negative pi over two; phase shift: x = negative pi over four

D: Amplitude = 3; period = 2π; phase shift: x = negative pi over four

Answer 2

The general formula is: y = A cos(Bx - C) + D
The amplitude is 3 because its always the absolute value of A.
| - 3 | = 3
The period is π/2 because for cosine graphs, you put 2π over B.
The phase shift is -π/4.

Answer 3

So its A

Answer 4

Thanks!

Answer 5

No problem!