What is the integral of 8/(x^3+4x) ?

The integral of 8/(x^3+4x) is 2ln|x|-ln|x^2+4|+C

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integral of 8/(x^3+4x)

\int \frac{8}{x ^{3} + 4 x} d x

2 ln ∣ x ∣ - ln x^{2} + 4 + C

Solution steps

\int \frac{8}{x ^{3} + 4 x} d x

Take the constant out:

\int a \cdot f (x) d x = a \cdot \int f (x) d x

= 8 \cdot \int \frac{1}{x ^{3} + 4 x} d x

Take the partial fraction of

\frac{1}{x ^{3} + 4 x} : \frac{1}{4 x} - \frac{x}{4 ( x ^{2} + 4 )}

= 8 \cdot \int \frac{1}{4 x} - \frac{x}{4 ( x ^{2} + 4 )} 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

= 8 (\int \frac{1}{4 x} d x - \int \frac{x}{4 ( x ^{2} + 4 )} d x)

\int \frac{1}{4 x} d x = \frac{1}{4} ln ∣ x ∣

\int \frac{x}{4 ( x ^{2} + 4 )} d x = \frac{1}{8} ln x^{2} + 4

= 8 (\frac{1}{4} ln ∣ x ∣ - \frac{1}{8} ln x^{2} + 4)

Simplify

8 (\frac{1}{4} ln ∣ x ∣ - \frac{1}{8} ln x^{2} + 4) : 2 ln ∣ x ∣ - ln x^{2} + 4

= 2 ln ∣ x ∣ - ln x^{2} + 4

Add a constant to the solution

= 2 ln ∣ x ∣ - ln x^{2} + 4 + C

What is the integral of 8/(x^3+4x) ?
The integral of 8/(x^3+4x) is 2ln|x|-ln|x^2+4|+C