# How to find antiderivative of a function in Octave

In this lesson I'll explain **how to calculate an antiderivative** of a mathematical function in Octave with some practical examples.

**What do you need?** To calculate the anti-derivatives you must have installed the Symbolic module on GNU Octave. To learn more, please click here.

Go to the Octave command line.

Define the independent variable symbol using the **syms** command. For example, the letter x

syms x

Now compute the antiderivative (**indefinite integral**) of the function **f(x)=1/x**

$$ \int \frac{1}{x} \ dx $$

Type **int()** command with the function expression 1/x as an argument. Then hit enter.

int(1/x)

Octave computes and returns the antiderivative of the function f(x) =1/x

ans = (sym) log(x)

The result is the antiderivative of 1/x is the primitive function F(x)=log(x)

The antiderivative is not a single function, it is a family of functions because you can add any constant (c) to the primitive function (F).

**Verify**. The antiderivative of 1/x is the logarithm of x plus any constant c. $$ \int \frac{1}{x} \ dx = \log(x) + c $$

Now you can calculate any antiderivative using Octave.