The integral \(\int e^x \left(\displaystyle\frac{x-1}{2x^2}\right)dx\) is equal to
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \(\displaystyle\frac{e^x}{2x}+C\), where C is constant of integration.
Splitting the fraction puts the integrand in the form \(e^x\left[f(x) + f'(x)\right]\):
\( \displaystyle \frac{x-1}{2x^2} = \frac{1}{2x} - \frac{1}{2x^2} \)
With \(f(x) = \displaystyle\frac{1}{2x}\),
\( \displaystyle f'(x) = -\frac{1}{2x^2} \)
By the standard result \(\int e^x\left[f(x) + f'(x)\right]dx = e^x f(x) + C\),
\( \displaystyle \int e^x\left(\frac{1}{2x} - \frac{1}{2x^2}\right)dx = \frac{e^x}{2x} + C \)