ExamBro
ExamBro
MHT CET · Maths · Indefinite Integration

If \(\int \frac{\sqrt{x}}{x(x+1)} d x=k \tan ^{-1} m+c\), (where \(c\) is constant of integration), then

  1. A \(\mathrm{k}=1, \mathrm{~m}=\sqrt{\mathrm{x}}\)
  2. B \(\mathrm{k}=2, \mathrm{~m}=\sqrt{\mathrm{x}}\)
  3. C \(\mathrm{k}=1, \mathrm{~m}=\mathrm{x}\)
  4. D \(\mathrm{k}=2, \mathrm{~m}=\mathrm{x}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\mathrm{k}=2, \mathrm{~m}=\sqrt{\mathrm{x}}\)

Step-by-step Solution

Detailed explanation

\(
I=\int \frac{\sqrt{x}}{x(x+1)} d x
\)
Put \(x \tan ^2 \theta \Rightarrow d x=2 \tan \theta \sec ^2 \theta d \theta\)
\(\therefore I=\int \frac{\tan \theta\left(2 \tan \theta \sec ^2 \theta\right)}{\tan ^2 \theta(1+\tan \theta)} d \theta \)
\( =2 \int \frac{\sec ^2 \theta}{\sec ^2 \theta} d \theta=2 \int d \theta=2 \theta \)
\( =2 \tan ^{-1} \sqrt{x}+c\)
Comparing with given data, \(\mathrm{k}=2, \mathrm{~m}=\sqrt{\mathrm{x}}\)