Jo S.

asked • 12/04/20

The Unit Circle and Trignomoetric Functions

Use the Sum Formula for Cosine to derive the following identity for the average rate of change of the cosine function:

cos (x + h) − cos x /h = cos x (cos h − 1)/h − sin x (sin h)/h

Note: You will learn in Calculus 1 that limh→0(cos h−1)/h = 0 and that limh→0 sin h/h = 1. It follows that the instantaneous rate of change of cos x is − sin x.

1 Expert Answer


Josie S. answered • 12/04/20

5 (1)

Experienced Teacher Specialized in High School Math

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