Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

$\int\frac{dx}{x(x^n+1)}$ is equal to :

Options:

$\frac{1}{n}\log(\frac{x^n}{x^n+1})+C$

$\frac{1}{n}\log(\frac{x^n+1}{x^n})+C$

$\log(\frac{x^n}{x^n+1})+C$

None of these

Correct Answer:

$\frac{1}{n}\log(\frac{x^n}{x^n+1})+C$

Explanation:

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

Put $x^n+1=t,nx^{n-1}dx=dt$

$I=\frac{1}{n}\int\frac{dt}{t(t-1)}=\frac{1}{n}\int(\frac{1}{t-1}-\frac{1}{t})dt=\frac{1}{n}\log(\frac{t-1}{t})+c=\frac{1}{n}\log(\frac{x^n}{x^n+1})+C$