Unit 3 - Objective 1 - Graphs of y = a sin x and y = a cos x
Quick Review

Sine and cosine curves are used in applications that involve circular motion.



The amplitude of y = sin x and y = cos x is 1, the maximum value. A constant in front of sin x or cos x changes the amplitude of the graph. The amplitude of y = A sin x is |A|. The amplitude of y = A cos x is |A|.

Example 1

  1. Given: y = sin theta has amplitude = |1| = 1

  2. Given: y = 1/2 sin theta has amplitude = |1/2| = 1/2

  3. Given: y = 3 cos theta has amplitude = |3| = 3

  4. Given: y = -5 cos theta has amplitude = |-5| = 5

Example 2

Graph y = 1/2 sin theta



Example 3

Graph y = -1/2 sin theta





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