**Reciprocal function.**
A function is called a *reciprocal function*
if

- If ,
increases without bound as approaches 0 from the right,
and decreases without bound as approaches 0 from the left.
In short, we write
as and as .
- If ,
decrease without bound as approaches 0 from the right,
and increases without bound as approaches 0 from the left.
In short, we write
as and as .

1. | 2. | |

**Linear rational functions.**
A function is called a *linear rational function*
if

(1) |

**Rational functions.**
A function is called a *rational function*
if

(2) |

with polynomial functions of degree and of degree .

Department of Mathematics