# Write the maximum and minimum values of 3 cos x + 4 sin x + 5. - Mathematics

Write the maximum and minimum values of 3 cos x + 4 sin x + 5.

#### Solution

$\text{ Let } f\left( x \right) = 3 \cos x + 4 \sin x + 5$
$\text{ We know that }$
$- \sqrt{3^2 + 4^2} \leq 3 \cos x + 4 \sin x \leq \sqrt{3^2 + 4^2}$
$\Rightarrow - 5 \leq 3 \cos x + 4 \sin x \leq 5$
$\Rightarrow - 5 + 5 \leq 3 \cos x + 4 \sin x + 5 \leq 5 + 5$
$\Rightarrow 0 \leq f(x) \leq 10$
$\text{ Hence, maximum and minimum vales of f(x) are 0 and 10 respectively } .$

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#### APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 7 Values of Trigonometric function at sum or difference of angles
Q 3 | Page 26