Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Indefinite Integration

Question:

The integral $\int \frac{2 x+x^3}{1+x^2} dx$ is equal to:

Options:

$\log \left(1+x^2\right)+x+C$ where C is a constant of integration

$\frac{1}{2} \log \left(1+x^2\right)+x^2+C$ where C is a constant of integration

$\frac{1}{2} \log \left(1+x^2\right)+\frac{1}{2} x+C$ where C is a constant of integration

$\frac{1}{2} \log \left(1+x^2\right)+\frac{x^2}{2}+C$ where C is a constant of integration

Correct Answer:

$\frac{1}{2} \log \left(1+x^2\right)+\frac{x^2}{2}+C$ where C is a constant of integration

Explanation:

The correct answer is Option (4) → $\frac{1}{2} \log \left(1+x^2\right)+\frac{x^2}{2}+C$ where C is a constant of integration

$\int \frac{2 x+x^3}{1+x^2} dx$

$=\int\frac{x^3+x}{x^2+1}+\frac{x}{x^2+1}dx$

$=\int x+\frac{1}{2}\frac{2x}{(x^2+1)}dx$

$=\frac{1}{2} \log \left(1+x^2\right)+\frac{x^2}{2}+C$