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Determine whether each function below is a rational function. If so, find the domain. If the function is not rational, state why not?
PLEASE HELP ME OUT

2007-07-19 11:19:23 · 3 answers · asked by algebra 3 1 in Science & Mathematics Mathematics

3 answers

A rational function is basically a division of two polynomial functions, and the denominator cannot equal zero. The domain is the set of numbers for which the function is rational (i.e., when the denominator is not equal to zero). So, in these problems, set the denominator equal to zero, and the values you get for x are not included in the domain:

1. x^2 - 3 = 0 --> x^2 = 3 --> x = +/- sq. rt. 3
Domain: (- infinity, - sq.rt. 3) U (- sq.rt. 3, + sq.rt. 3) U (+ sq.rt. 3, + infinity)

2. x-2 = 0 --> x = 2
Domain: (- infinity, 2) U (2, +infinity)

3. x^2 - 1 = 0 --> x^2 = 1 --> x = +/- 1
Domain: (-infinity, -1) U (-1,1) U (1, infinity)

Hope this helps!

2007-07-19 11:37:28 · answer #1 · answered by Ellee C. 2 · 1 0

is it more of like this:

[1]. f(x) = (x^3 - 5x + 7)/(x^2 - 3)
[2]. ch(x) = (x + 2)/(x - 2)
[3]. w(x) = (12 - 2x)/(x^2 - 1)

??

if so then:
[1]. i'm not too sure about this one. I think you have to factorise it first or something to see whether or not it gives you any x.
[2]. this is a function. not sure what the domain is (too lazy) but it has a domain.
[3]. this is also a function. it has domain too..

2007-07-19 11:34:10 · answer #2 · answered by Anonymous · 0 0

they are all rational functions and the domain is just the part on the bottom of the fraction

a rational function is just a function that can be written as a ratio of two polynomials.

2007-07-19 11:24:51 · answer #3 · answered by climberguy12 7 · 0 3

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