Cos (X + A) - Mathematics

cos (x + a)

Solution

$\frac{d}{dx}\left[ \cos \left( x + a \right) \right]$
$= \frac{d}{dx}\left( \cos x \cos a - \sin x \sin a \right)$
$= \cos a\frac{d}{dx}\left( \cos x \right) - \sin a \frac{d}{dx}\left( \sin x \right)$
$= - \cos a \sin x - \sin a \cos x$
$= - \left( \sin x \cos a + \cos x \sin a \right)$
$= - \sin\left( x + a \right)$

Concept: The Concept of Derivative - Algebra of Derivative of Functions
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APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 30 Derivatives
Exercise 30.3 | Q 17 | Page 34