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# Identify A Common Series

APCALC-D0UV1B

Identify the series as a function of $x$:

$$1-x-\cfrac{{ x }^{ 2 }}{2!}+\cfrac{{ x }^{ 3 }}{3!}+\cfrac{{ x }^{ 4 }}{4!}-\cfrac{{ x }^{ 5 }}{5!}-\cfrac{{ x }^{ 6 }}{6!}+\cdots$$

A

$e^{-x}$

B

$\sin x-\cos x$

C

$\cos x-\sin x$

D

$\arctan x$