#### Answer

$0$

#### Work Step by Step

$\cos 40\cos 50-\sin 40\sin 50=\cos \left( 40+50\right) =\cos 90=0$

Published by
Pearson

ISBN 10:
013421742X

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

$0$

$\cos 40\cos 50-\sin 40\sin 50=\cos \left( 40+50\right) =\cos 90=0$

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