website/content/blog/2017-03-09-simplifying-expressions-octave.md

---
id: 2115
title: Simplifying Expressions with Octave
date: 2017-03-09T02:09:58+00:00
author: Brandon Rozek
layout: post
guid: https://brandonrozek.com/?p=2115
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---
Octave is a high level programming language intended for numerical computations. One of the cool features of this is that with symbolic expressions, you can then simplify mathematical expressions.

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## Setup

First install [Octave](https://www.gnu.org/software/octave/) and the [symbolic package](https://octave.sourceforge.io/symbolic/) using the website or your package manager of choice.

Then in octave type in the following code

```MATLAB
pkg load symbolic
```


## Usage

For every variable not defined earlier in your expression, make sure to declare it as a symbolic data type

```MATLAB
syms x y
```

Then make an expression

```MATLAB
expr = y + sin(x)^2 + cos(x)^2
```

You can then ask Octave to simplify the expression for you

```MATLAB
simp_expr = simplify(expr)
```

Displaying it shows it as

```MATLAB
(sym) y + 1
```

Which is indeed a simplification using a trig identity 🙂

Update: Octave's symbolic is based on [SymPy](https://www.sympy.org/en/index.html). If you're confortable with Python, I recommend checking it out.