First slide

Methods of integration

Question

$\int \frac{dx}{\sin x - \cos x + \sqrt{2}}$ is equal to

Moderate

A

$- \frac{1}{\sqrt{2}} \tan (\frac{x}{2} + \frac{π}{8}) + C$
B

$\frac{1}{\sqrt{2}} \tan (\frac{x}{2} + \frac{π}{8}) + C$
C

$\frac{1}{\sqrt{2}} \cot (\frac{x}{2} + \frac{π}{8}) + C$
D

$- \frac{1}{\sqrt{2}} \cot (\frac{x}{2} + \frac{π}{8}) + C$

Solution

$\begin{array}{l} \int \frac{dx}{\sin x - \cos x + \sqrt{2}} \\ = \int \frac{dx}{\sin x \frac{\sqrt{2}}{\sqrt{2}} - \cos x \frac{\sqrt{2}}{\sqrt{2}} + \sqrt{2}} \\ = \int \frac{dx}{\sqrt{2} (\sin xsin \frac{π}{4} - \cos xcos \frac{π}{4} + 1)} \\ = \frac{1}{\sqrt{2}} \int \frac{dx}{1 - \cos (x + \frac{π}{4})} \\ = \frac{1}{\sqrt{2}} \int \frac{dx}{1 - \cos 2 (\frac{x}{2} + \frac{π}{8})} = \frac{1}{\sqrt{2}} \int \frac{dx}{2 \sin^{2} (\frac{x}{2} + \frac{π}{8})} \\ = \frac{1}{2 \sqrt{2}} \int {cosec}^{2} (\frac{x}{2} + \frac{π}{8}) dx \\ = - \frac{1}{2 \sqrt{2}} \cdot \frac{- \cot (\frac{x}{2} + \frac{π}{8})}{\frac{1}{2}} + C = \frac{1}{\sqrt{2}} \cot (\frac{x}{2} + \frac{π}{8}) + C \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App