#### Answer

Not needed.

#### Work Step by Step

The trigonometric substitution is not needed and instead, we can use the substitution $ u=9−x^2$.

Published by
W. H. Freeman

ISBN 10:
1464125260

ISBN 13:
978-1-46412-526-3

Not needed.

The trigonometric substitution is not needed and instead, we can use the substitution $ u=9−x^2$.

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