# When finding the domain of a function or fraction.. is x cannot equal -3 and x cannot equal 5 the same as (-infinity,-3)union(-3,5)union(5,infinity)?

sciencesolve | Teacher | (Level 3) Educator Emeritus

Posted on

You should remember that the domain of the function consists of all values that make the function to exist, hence, in the provided case, the function ceases to exist for `x=5`  and `x=-3` , hence, these two values needs to be excluded from domain of definition.

Domain = `R - {-3 , 5}`

You may use the interval notation to write the domain of the function such that:

`(-oo,-3)U(-3,5)U(5,+oo)`  (the symbol "U" represents the union)

Hence, using the interval notation to write the domain of the function that is not defined at `x=-3`  and `x=5`  , yields `(-oo,-3)U(-3,5)U(5,+oo).`

Sources:

mrcoolguy555 | Student, College Freshman | (Level 1) Honors

Posted on

I didn't understand what you were trying to say honestly. I only asked one question, if those mean the same thing and you didn't answer that. But thanks for your time anyway.