Problem 211
Easy Roots and Binomials

Evaluate the integral: I = integral (3x+2)/(2x²+x-3) dx

Evaluate the integral: $$ I = \int \frac{3x+2}{2x^2+x-3}\,dx. $$

Explanation of Method

Factoring the denominator and decomposing into partial fractions reduces the integral to two elementary logarithms.

  1. Factor $2x^2+x-3=(2x+3)(x-1)$.
  2. Decompose into partial fractions.
  3. Integrate term by term and combine logs.

Step 1 · Factor and set up partial fractions

$$ 2x^2+x-3 = (2x+3)(x-1), \qquad \frac{3x+2}{(2x+3)(x-1)} = \frac{A}{2x+3} + \frac{B}{x-1}. $$

Multiplying through: $3x+2=A(x-1)+B(2x+3)$. Setting $x=1$: $5=5B$, so $B=1$. Setting $x=-\tfrac32$: $-\tfrac52=-\tfrac52A$, so $A=1$.

Step 2 · Integrate

$$ I = \int \left(\frac{1}{2x+3} + \frac{1}{x-1}\right) dx = \frac12\ln|2x+3| + \ln|x-1| + C. $$

Step 3 · Combine logarithms

$$ I = \ln\left|(x-1)\sqrt{2x+3}\right| + C. $$


Summary Table

Coefficient Value
$A$$1$
$B$$1$

Additional Notes

Result

The solution to the integral is:

$$ I = \ln\left|(x-1)\sqrt{2x+3}\right| + C. $$