Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

$\int e^{3 \log x}\left(x^4+1\right)^{-1} d x$ is equal

Options:

$\log \left(x^4+1\right)+C$

$\frac{1}{4} \log \left(x^4+1\right)+C$

$-\log \left(x^4+1\right)+C$

none of these

Correct Answer:

$\frac{1}{4} \log \left(x^4+1\right)+C$

Explanation:

We have,

$I =\int e^{3 \log x}\left(x^4+1\right)^{-1} d x=\int \frac{e^{\log x^3}}{x^4+1} d x=\int \frac{x^3}{x^4+1} d x$

$\Rightarrow I =\frac{1}{4} \int \frac{1}{x^4+1} d\left(x^4+1\right)=\frac{1}{4} \log \left(x^4+1\right)+C$