### 3.1.3 Testing for undefined and infinity symbols

The isinf command checks whether its argument is an infinity (unsigned, positive or negative) or not.

The isnan command checks whether its argument is undefined or not.

#### Examples

isnan(0/0)

true |  |  |  |  |  |  |  |  |  |

isnan(0/1)

false |  |  |  |  |  |  |  |  |  |

isinf(0/1)

false |  |  |  |  |  |  |  |  |  |

isinf(1/0)

true |  |  |  |  |  |  |  |  |  |