# Integrals by partial fraction expansion Calculator

## Get detailed solutions to your math problems with our Integrals by partial fraction expansion step-by-step calculator. Practice your math skills and learn step by step with our math solver. Check out all of our online calculators here!

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### Difficult Problems

1

Solved example of integrals by partial fraction expansion

$\int\frac{1}{x\left(x+1\right)}dx$
2

Rewrite the fraction $\frac{1}{x\left(x+1\right)}$ in $2$ simpler fractions using partial fraction decomposition

$\frac{1}{x\left(x+1\right)}=\frac{A}{x}+\frac{B}{x+1}$
3

Find the values of the unknown coefficients. The first step is to multiply both sides of the equation by $x\left(x+1\right)$

$1=x\left(x+1\right)\left(\frac{A}{x}+\frac{B}{x+1}\right)$
4

Multiplying polynomials

$1=\frac{Ax\left(x+1\right)}{x}+\frac{Bx\left(x+1\right)}{x+1}$
5

Simplifying

$1=A\left(x+1\right)+Bx$
6

Expand the polynomial

$1=Ax+A+Bx$
7

Assigning values to $x$ we obtain the following system of equations

$\begin{matrix}1=A&\:\:\:\:\:\:\:(x=0) \\ 1=-B&\:\:\:\:\:\:\:(x=-1)\end{matrix}$
8

Proceed to solve the system of linear equations

$\begin{matrix}1A & + & 0B & =1 \\ 0A & - & 1B & =1\end{matrix}$
9

Rewrite as a coefficient matrix

$\left(\begin{matrix}1 & 0 & 1 \\ 0 & -1 & 1\end{matrix}\right)$
10

Reducing the original matrix to a identity matrix using Gaussian Elimination

$\left(\begin{matrix}1 & 0 & 1 \\ 0 & 1 & -1\end{matrix}\right)$
11

The integral of $\frac{1}{x\left(x+1\right)}$ in decomposed fraction equals

$\int\left(\frac{1}{x}+\frac{-1}{x+1}\right)dx$
12

The integral of the sum of two or more functions is equal to the sum of their integrals

$\int\frac{1}{x}dx+\int\frac{-1}{x+1}dx$
13

Apply the formula: $\int\frac{n}{x+b}dx$$=n\ln\left|x+b\right|$, where $b=1$ and $n=-1$

$\int\frac{1}{x}dx-\ln\left|x+1\right|$
14

The integral of the inverse of the lineal function is given by the following formula, $\displaystyle\int\frac{1}{x}dx=\ln(x)$

$\ln\left|x\right|-\ln\left|x+1\right|$
15

As the integral that we are solving is an indefinite integral, when we finish we must add the constant of integration

$\ln\left|x\right|-\ln\left|x+1\right|+C_0$
16

The difference of two logarithms of same base is equal to the logarithm of the division

$\ln\left|\frac{x}{x+1}\right|+C_0$

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