Get Answers to all your Questions

header-bg qa

explain solution RD Sharma class 12 Chapter 18 Indefinite Integrals exercise 18.30 question 50

Answers (1)

Answer:

                -\frac{1}{4 x}+\frac{7}{8} \tan ^{-1}\left(\frac{x}{2}\right)+C

Hint:

            To solve this integration, we use partial fraction method   

Given:

            \int \frac{2 x^{2}+1}{x^{2}\left(x^{2}+4\right)}dx

Explanation:

Let

I= \int \frac{2 x^{2}+1}{x^{2}\left(x^{2}+4\right)}dx

Now let’s separate the fraction \frac{2 x^{2}+1}{x^{2}\left(x^{2}+4\right)} through the partial fraction

Put

\begin{aligned} &4 A=1 \\ &A=\frac{1}{4} \\ &A+B=2 \\ &B=2-A \\ &B=2-A \\ &B=2-\frac{1}{4} \\ &B=\frac{7}{4} \end{aligned}

Equating both side

\begin{aligned} &\frac{2 y+1}{y(y+4)}=\frac{1}{4 y}+\frac{7}{4(y+4)} \\ &=\frac{1}{4 x^{2}}+\frac{7}{4\left(x^{2}+4\right)} \end{aligned}

\begin{aligned} &I=\frac{1}{4} \int \frac{d x}{x^{2}}+\frac{7}{4} \int \frac{1}{x^{2}+4} d x \\ &I=\frac{1}{4} \cdot\left(\frac{1}{-x}\right)+\frac{7}{4} \cdot\left(\frac{1}{2}\right) \tan ^{-1} \frac{x}{2}+C \\ &I=\frac{-1}{4 x}+\frac{7}{8} \tan ^{-1} \frac{x}{2}+C \end{aligned}

Posted by

infoexpert27

View full answer

Crack CUET with india's "Best Teachers"

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