Question

Use the graph below to answer the question that follows:

cosine graph with points at 0, negative 1 and pi over 2, 3, and pi, negative 1

What are the amplitude, period, and midline of the function?
A) Amplitude: 4; period: π; midline: y = 1
B) Amplitude: 4; period: 2π; midline: y = 5
C) Amplitude: 2; period: 2π; midline: y = 5
D) Amplitude: 2; period: π; midline: y = 1

Answer 1

D) Amplitude: 2; period: π; midline: y = 1

Explanation:

The question is much more easily answered from the graph than from the description of the graph.

The amplitude is the extent of the peak above the midline (2), or half the peak-to-peak value (4/2=2). The midline is the line halfway between the peaks (1). The period is the horizontal distance between peaks of the same polarity (π).