find the domain of the following rational function

r(x)=2(x2-6x-40)

3(x2-100)

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- Jul 7th 2008, 06:55 PMnae33finding domain
find the domain of the following rational function

r(x)=__2(x2-6x-40)__

3(x2-100) - Jul 7th 2008, 07:05 PMmr fantastic
- Jul 7th 2008, 07:05 PMReckoner
Unless otherwise specified, we usually take the domain of a function to be all real numbers for which the function is defined.

So consider what values of would make undefined. Those are the values that are excluded from the domain. (Hint: look for values that would cause things like a division by zero or the taking of the square root/logarithm of a negative number). - Jul 7th 2008, 07:09 PMnae33
when i did it i got -10 and 10 as the domain because of the (x2-100)(Worried)

- Jul 7th 2008, 07:13 PMmr fantastic
- Jul 7th 2008, 07:14 PMReckoner
Be careful. The domain is the values for which the function

*is*defined. But when , the function is*undefined*(due to a division by zero). Thus your answer should be reversed: the domain is all real numbers not equal to . If you want to write this with set notation, there are several ways:

or

for example. - Jul 7th 2008, 07:23 PMnae33
sorry i ment not = to. i couldnt find the equal sign with the line going through