#### Answer

$-1$

#### Work Step by Step

$\cos \left( \arccos x\right) =x\Rightarrow \cos \left( \arccos \left( -1\right) \right) =-1$

Published by
Pearson

ISBN 10:
013421742X

ISBN 13:
978-0-13421-742-0

$-1$

$\cos \left( \arccos x\right) =x\Rightarrow \cos \left( \arccos \left( -1\right) \right) =-1$

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