Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:
The value of the integration \(\int \frac{dx}{(1+e^{x})(1-e^{-x})}\) is
Options:
\(\frac{e^{2}}{1+e^{2}}\)
\(-\frac{e^{2}}{1+e^{2}}\)
\(\frac{1}{1+e^{2}}\)
\(-\frac{1}{1+e^{2}}\)
Correct Answer:
\(-\frac{1}{1+e^{2}}\)
Explanation:
Let \(1+e^{2}=t\) so \(e^{x}dx=dt\) \(\begin{aligned}\int \frac{dx}{(1+e^{x})(1-e^{-x})}&=\int \frac{e^{x}}{(1+e^{x})^{2}}dx\\ &=\frac{-1}{1+e^{2}}\end{aligned}\)