# Rational Functions and Multiplying and Dividing Rational Expressions

# Rational Functions and Multiplying and Dividing Rational Expressions

Defns ☺ A rational expression is an expression that can be written as
where P and Q are polynomials and Q
is not 0. Give examples.☺ Rational functions Give examples.☺ The domain of a functions is the set of all permissible
-values. For rational functions, the domain consists of all real numbers
except those that make the denominator 0. |

Ex 1 Find the domain of each rational function . Write answers using set notation.

Fundamental Principle of Rational
Expressions For any rational expression or, simply , *Always Factor First * |

Multiplying and Dividing Rational ExpressionsLet and S be polynomials . Then where and where and *Always Factor First * |

Ex 3 Multiply or divide .

Ex 4 (if time permits) A company’s cost per book for printing particular books is given by the rational function . Find the cost of printing

a) 100 books

b) 1000 books

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