Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Determinants

Question:

If $\int\limits_0^1 \frac{e^x}{1+x} d x=K$, then $\int\limits_0^1 \frac{e^x}{(1+x)^2} d x$ is equal to :

Options:

$K-1+\frac{e}{2}$

$K+1-\frac{e}{2}$

$K-1-\frac{e}{2}$

$K+1+\frac{e}{2}$

Correct Answer:

$K+1-\frac{e}{2}$

Explanation:

so $I=\int\limits_0^1 \frac{e^x}{1+x} d x$

we get  $I = \left[\frac{e^x}{1+x}\right]_0^1+\int\limits_0 \frac{e^x}{1+x^2} d x=K$  (as given)

So $\int\limits_0^1 \frac{e^x}{(1+x)^2} d x=K-\left[\frac{e x}{1+x}\right]_0^1$

$\Rightarrow \int\limits_0^1 \frac{e^x d x}{(1+x)^2}=K-\left[\frac{e}{2}-1\right]$

$\Rightarrow \int\limits_0^1 \frac{e^x}{(1+x)^2} d x=K-\frac{e}{2}+1$