Get Answers to all your Questions

header-bg qa

Please Solve RD Sharma Class 12 Chapter 19 Definite Integrals Exercise Revision Exercise Question 3 Maths Textbook Solution.

Answers (1)

Answer: \frac{16}{3}

Given: \int_{1}^{5} \frac{x}{\sqrt{2 x-1}} d x

Hint: Let the denominator(2x-1) = t

Solution:

\int_{1}^{5} \frac{x}{\sqrt{2 x-1}} d x

Let  t=2 x-1=>x=\frac{t+1}{2}

dt = 2dx                   (differentiating w.r.t  x)

\begin{aligned} &I=\int_{1}^{5} \frac{t+1}{\frac{2}{\sqrt{t}}} \times \frac{d t}{2} \\ & \end{aligned}

I=\int_{1}^{5} \frac{t+1}{2 \sqrt{t}} d t=\frac{1}{4} \int_{1}^{5} \sqrt{t}+(t)^{\frac{-1}{2}} d t

=\frac{1}{4}\left(\frac{t^{\frac{3}{2}}}{\frac{3}{2}}+\frac{t^{\frac{1}{2}}}{\frac{1}{2}}\right)_{1}^{5}

=\frac{1}{4}\left(\frac{2}{3}(2 x-1)^{\frac{3}{2}}+2(2 x-1)^{\frac{1}{2}}\right)_{1}^{5}

\begin{aligned} &=\frac{1}{4}\left(\frac{2}{3}(27-1)+2(3-1)\right) \\ & \end{aligned}

=\frac{1}{4}\left(\frac{2}{3}(26)+2(2)\right)

\begin{aligned} &=\frac{1}{4}\left(\frac{52+12}{3}\right) \\ & \end{aligned}

=\frac{1}{4} \times \frac{64}{3} \\

=\frac{16}{3}

Posted by

infoexpert27

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads