# Documentation

### This is machine translation

Translated by
Mouseover text to see original. Click the button below to return to the English verison of the page.

# `Type`::`Zero`

Type and property representing zero

MATLAB live scripts support most MuPAD functionality, though there are some differences. For more information, see Convert MuPAD Notebooks to MATLAB Live Scripts.

## Syntax

```testtype(`obj`, Type::Zero)
assume(`x`, Type::Zero)
is(`ex`, Type::Zero)
```

## Description

`testtype(obj, Type::Zero )` is equivalent to `iszero(obj)`. `Type::Zero` is a property, too, which can be used in an `assume` call.

The call `testtype(obj, Type::Zero)` is equivalent to `iszero(obj)`, which performs a syntactical test if `obj` is zero. If it is, the call returns `TRUE`, otherwise, `FALSE` is returned.

The call `assume(x, Type::Zero)` marks the identifier `x` as zero.

The call `is(ex, Type::Zero)` derives, whether the expression `ex` is zero (or this property can be derived).

This type represents a property that can be used in `assume` and `is`.

The call `assume(x = 0)` has the same meaning as `assume(x, Type::Zero)`.

## Examples

### Example 1

`testtype` determines the syntactical equality to zero:

`testtype(0.0, Type::Zero)`

`testtype(x, Type::Zero)`

### Example 2

`Type::Zero` can be used within `assume` and `is`:

`is(x, Type::Zero)`

Assumption that `x` is zero:

```assume(x, Type::Zero): is(x^2, Type::Zero)```

The next example shows the difference between `testtype` and `is`:

`is(x, Type::Zero), testtype(x, Type::Zero)`

Now the property of `x` is removed:

```delete x: is(x, Type::Zero), testtype(x, Type::Zero)```

A positive number cannot be zero:

```assume(x > 0): is(x, Type::Zero), testtype(x, Type::Zero)```

But in the next example `x` could be zero:

```assume(x >= 0): is(x, Type::Zero), testtype(x, Type::Zero)```

`delete x:`

## Parameters

 `obj` Any MuPAD® object `x` An identifier or a mathematical expression containing identifiers `ex`