Skip to main contentSkip to solution

The integral ∫ex(x−12x2)dx\int e^x\left(\frac{x-1}{2x^2}\right)dx is equal to

Solution

✅ Correct Option: 1

The fraction can be simplified:

x−12x2=x2x2−12x2\frac{x-1}{2x^2} = \frac{x}{2x^2} - \frac{1}{2x^2}

=12x−12x2= \frac{1}{2x} - \frac{1}{2x^2}

The integral becomes:

∫ex(12x−12x2)dx\int e^x\left(\frac{1}{2x} - \frac{1}{2x^2}\right)dx


The integration formula for exe^x is:

∫ex[f(x)+f′(x)]dx=ex⋅f(x)+C\int e^x[f(x) + f'(x)]dx = e^x \cdot f(x) + C

When exe^x is multiplied by a function plus its derivative, the integral is exe^x times that function.


Let f(x)=12xf(x) = \frac{1}{2x}

The derivative is:

f′(x)=ddx(12x)f'(x) = \frac{d}{dx}\left(\frac{1}{2x}\right)

=−12x2= -\frac{1}{2x^2}


Check if f(x)+f′(x)f(x) + f'(x) matches the expression:

f(x)+f′(x)=12x+(−12x2)f(x) + f'(x) = \frac{1}{2x} + \left(-\frac{1}{2x^2}\right)

=12x−12x2= \frac{1}{2x} - \frac{1}{2x^2}

This matches the integrand.


Applying the formula with f(x)=12xf(x) = \frac{1}{2x}:

∫ex(12x−12x2)dx=ex⋅12x+C\int e^x\left(\frac{1}{2x} - \frac{1}{2x^2}\right)dx = e^x \cdot \frac{1}{2x} + C

=ex2x+C= \frac{e^x}{2x} + C

Therefore, the integral equals ex2x+C\frac{e^x}{2x} + C

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question