Domain In a rational expression

[sashugarts]

Hi guys,

I'm taking a summer school course online and we are learning about rational expressions.
All of a sudden we are on chapter 12 trying to learn what a domain is.
I've spent maybe an hour on this, if someone could help me that would be great!

Thanks,
Alex

 

[mmm4444bot]

The domain is always some set of Real numbers.

Specifically, the domain contains every Real number that a person could substitute for the variable to get a valid result.

With Rational expressions, we may not substitute any value for the variable that causes the denominator to evaluate to zero because division by zero is not defined in the Real-number system.

In general, to determine some algebraic ratio's domain, one must determine which Real numbers cause that expression's denominator to become zero; the domain is then all remaining Real numbers. (If the given expression's denominator contains a square root -- or something other than just a polynomial -- then some additional considerations must be made to determine the domain.)

Do you have a particular exercise which is giving you trouble?