# If π 2 < X < 3 π 2 , Then √ 1 − Sin X 1 + Sin X is Equal to - Mathematics

MCQ

If $\frac{\pi}{2} < x < \frac{3\pi}{2},\text{ then }\sqrt{\frac{1 - \sin x}{1 + \sin x}}$ is equal to

#### Options

• sec x − tan x

•  sec x + tan x

• tan x − sec x

• none of these

#### Solution

tan x − sec x
$\sqrt{\frac{1 - \sin x}{1 + \sin x}}$
$= \sqrt{\frac{\left( 1 - \sin x \right)\left( 1 - \sin x \right)}{\left( 1 + \sin x \right)\left( 1 - \sin x \right)}}$
$= \sqrt{\frac{\left( 1 - \sin x \right)^2}{1 - \sin^2 x}}$
$= \sqrt{\frac{\left( 1 - \sin x \right)^2}{\cos^2 x}}$
$= \frac{\left( 1 - \sin x \right)}{- cos x} \left[\text{ as,} \frac{\pi}{2} < x < \frac{3\pi}{2},\text{ so }\cos\theta\text{ will be negative }\right]$
$= - \left( sec x - \tan x \right)$
$= - sec x + \tan x$

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#### APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 5 Trigonometric Functions
Q 3 | Page 41