The integral $I =\int e^x\left(\frac{x-1}{3x^2}\right) dx$ is equal to
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $\frac{1}{3x}e^x+C$, where C is constant of integration
$I=\int e^x\left(\frac{x-1}{3x^2}\right)\,dx$
Rewrite:
$I=\frac{1}{3}\int e^x\left(\frac{x-1}{x^2}\right)\,dx$
Note that:
$\frac{d}{dx}\left(\frac{e^x}{x}\right)=\frac{e^x(x-1)}{x^2}$
Therefore:
$I=\frac{1}{3}\cdot \frac{e^x}{x}+C$
$I=\frac{1}{3x}e^x + C$