What is the integral of x/(x^2-2x-15) ?

The integral of x/(x^2-2x-15) is 3/8 ln|x+3|+5/8 ln|x-5|+C

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integral of x/(x^2-2x-15)

\int \frac{x}{x ^{2} - 2 x - 15} d x

\frac{3}{8} ln ∣ x + 3 ∣ + \frac{5}{8} ln ∣ x - 5 ∣ + C

Solution steps

\int \frac{x}{x ^{2} - 2 x - 15} d x

Take the partial fraction of

\frac{x}{x ^{2} - 2 x - 15} : \frac{3}{8 ( x + 3 )} + \frac{5}{8 ( x - 5 )}

= \int \frac{3}{8 ( x + 3 )} + \frac{5}{8 ( x - 5 )} d x

Apply the Sum Rule:

\int f (x) \pm g (x) d x = \int f (x) d x \pm \int g (x) d x

= \int \frac{3}{8 ( x + 3 )} d x + \int \frac{5}{8 ( x - 5 )} d x

\int \frac{3}{8 ( x + 3 )} d x = \frac{3}{8} ln ∣ x + 3 ∣

\int \frac{5}{8 ( x - 5 )} d x = \frac{5}{8} ln ∣ x - 5 ∣

= \frac{3}{8} ln ∣ x + 3 ∣ + \frac{5}{8} ln ∣ x - 5 ∣

Add a constant to the solution

= \frac{3}{8} ln ∣ x + 3 ∣ + \frac{5}{8} ln ∣ x - 5 ∣ + C

What is the integral of x/(x^2-2x-15) ?
The integral of x/(x^2-2x-15) is 3/8 ln|x+3|+5/8 ln|x-5|+C