MCQ
$\mathop {\lim }\limits_{x \to 0} \frac{{\sin (2 + x) - \sin (2 - x)}}{x} = $
  • A
    $\sin 2$
  • B
    $2\sin 2$
  • $2\cos 2$
  • D
    $2$

Answer

Correct option: C.
$2\cos 2$
c
(c) Apply formula of $\sin C - \sin D$,

$i.e.,$ $\mathop {\lim }\limits_{x \to 0} \frac{{\sin (2 + x) - \sin (2 - x)}}{x} = \mathop {\lim }\limits_{x \to 0} \frac{{2\cos 2.\sin x}}{x}$

$ = 2\cos 2.\mathop {\lim }\limits_{x \to 0} \frac{{\sin x}}{x} = 2\cos 2$

You may also apply $L-$ Hospital rule.

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