Get Answers to all your Questions

header-bg qa

Provide Solution For  R.D.Sharma Maths Class 12 Chapter 19 definite Integrals Exercise 19.1 Question 32 Maths Textbook Solution.

Answers (1)

Answer:

        2log2-1

Hint: Use indefinite integral formula and then put the limits to solve this integral

Given:

             \int_{1}^{2}log\; xdx

Solution:

              \int_{1}^{2}log\; xdx

Integrating by parts, then

\begin{aligned} &\int_{1}^{2} \log x d x=\left[\log x \int 1 d x\right]_{1}^{2}-\int_{1}^{2}\left[\frac{d}{d x}(\log x) \int 1 d x\right] d x \\ &=[\log x x]_{1}^{2}-\int_{1}^{2} \frac{1}{x} x d x \quad\left[\because \int 1 d x=x ; \frac{d}{d x}(\log x)=\frac{1}{x}\right] \\ &=[2 \log 2-11 \log 1]-\int_{1}^{2} 1 d x \quad\left[\because \int 1 d x=x, \log 1=0\right] \end{aligned}

\begin{aligned} &=[2 \log 2-1(0)]-[x]_{1}^{2} \\ &=2 \log 2-[2-1] \\ &=2 \log 2-1 \end{aligned}

 

Posted by

infoexpert21

View full answer

Crack CUET with india's "Best Teachers"

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