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Rational Functions

A rational part is defined as the quotient of polynomials in which the denominator has a caste of at least 1 . In other words, in that location must be a variable in the denominator.

The general form of a rational function is

p ( ten ) q ( 10 )

, where

p ( x )

and

q ( 10 )

are polynomials and

q ( 10 ) 0

.

Examples:

y = 3 ten , y = 2 x + 1 10 + 5 , y = ane x 2

The parent part of a rational role is f ( x ) = one x and the graph is a hyperbola .

The domain and range is the set of all real numbers except 0 .

Domain: { x | x 0 } Range: { y | y 0 }

Excluded value

In a rational function, an excluded value is any x -value that makes the office value y undefined. So, these values should be excluded from the domain of the role.

For example, the excluded value of the function y = ii x + 3 is –3. That is, when ten = 3 , the value of y is undefined.

And then, the domain of this function is set of all real numbers except iii .

Asymptotes

An asymptote is a line that the graph of the function approaches, simply never touches. In the parent function f ( x ) = 1 x , both the x - and y -axes are asymptotes. The graph of the parent function volition get closer and closer to just never touches the asymptotes.

A rational function in the form y = a x b + c has a vertical asymptote at the excluded value, or x = b , and a horizontal asymptote at y = c .

See besides: Graphing Rational Functions