# lhs

Left side (LHS) of equation

## Syntax

``lhs(eqn)``

## Description

example

````lhs(eqn)` returns the left side of the symbolic equation `eqn`. The value of `eqn` also can be a symbolic condition, such as `x > 0`. If `eqn` is an array, then `lhs` returns an array of the left sides of the equations in `eqn`.```

## Examples

### Find Left Side of Equation

Find the left side of the equation `2*y == x^2` by using `lhs`.

First, declare the equation.

```syms x y eqn = 2*y == x^2 ```
```eqn = 2*y == x^2```

Find the left side of `eqn` by using `lhs`.

`lhsEqn = lhs(eqn)`
```lhsEqn = 2*y```

### Find Left Side of Condition

Find the left side of the condition `x + y < 1` by using `lhs`.

First, declare the condition.

```syms x y cond = x + y < 1```
```cond = x + y < 1```

Find the left side of `cond` by using `lhs`.

`lhsCond = lhs(cond)`
```lhsCond = x + y```

Note

Conditions that use the `>` operator are internally rewritten using the `<` operator. Therefore, `lhs` returns the original right side. For example, `lhs(x > a)` returns `a`.

### Find Left Side of Equations in Array

For an array that contains equations and conditions, `lhs` returns an array of the left sides of those equations or conditions. The output array is the same size as the input array.

Find the left side of the equations and conditions in the vector `V`.

```syms x y V = [y^2 == x^2, x ~= 0, x*y >= 1]```
```V = [ y^2 == x^2, x ~= 0, 1 <= x*y]```
`lhsV = lhs(V)`
```lhsV = [ y^2, x, 1]```

Because any condition using the `>=` operator is internally rewritten using the `<=` operator, the sides of the last condition in `V` are exchanged.

## Input Arguments

collapse all

Equation or condition, specified as a symbolic equation or condition, or a vector, matrix, or multidimensional array of symbolic equations or conditions.