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`Type`::`Negative`

Type and property representing negative numbers

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::Negative)
assume(`x`, Type::Negative)
is(`ex`, Type::Negative)
```

Description

`Type::Negative` represents negative numbers. `Type::Negative` is a property, too, which can be used in an `assume` call.

The call `testtype(obj, Type::Negative)` checks, whether `obj` is a negative real number and returns `TRUE`, if it holds, otherwise `FALSE`.

`testtype` only performs a syntactical test identifying MuPAD® objects of type `DOM_INT`, `DOM_RAT` and `DOM_FLOAT` and checks, if `bool(obj < 0)` holds. This does not include arithmetical expressions such as `-exp(1)`, which are not identified as of type `Type::Negative`.

The call `assume(x, Type::Negative)` marks the identifier `x` as a negative real number.

The call `is(ex, Type::Negative)` derives, whether the expression `ex` is a negative real number (or this property can be derived).

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

Instead of `Type::Negative` the assumption can also be `assume(x < 0)`.

Examples

Example 1

The following numbers are of type `Type::Negative`:

```testtype(-2, Type::Negative), testtype(-3/4, Type::Negative), testtype(-0.123, Type::Negative), testtype(-1, Type::Negative), testtype(-1.02, Type::Negative)```

The following expressions are exact representations of negative numbers, but syntactically they are not of `Type::Negative`:

```testtype(-exp(1), Type::Negative), testtype(-PI^2 - 5, Type::Negative), testtype(-sin(2), Type::Negative)```

Example 2

Assume an identifier is negative:

```assume(x, Type::Negative): is(x, Type::Negative)```

This is equal to:

```assume(x < 0): is(x < 0)```

Also negative numbers are real:

```assume(x, Type::Negative): is(x, Type::Real)```

However, real numbers can be negative or not:

```assume(x, Type::Real): is(x, Type::Negative)```

`delete x:`

Parameters

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