Finding the Domain of functions

[jtw2e2]

Hi, I'm having trouble finding the domain of several functions. I understand that this requires finding the domain of each function and then finding out their intersection, but my current problem is simply finding the domain.

For example:

f(x)= ?(8+x^2)
g(x)= ?(-2-x)

For the first function, I get for the domain x^2 ? -8 but how do you proceed? You can't take the ? of a negative!

Here's my work for the first part:
Set radicand ? 0
8+x^2 ? 0
x^2 ? -8

 

[mmm4444bot]

… x^2 ? -8

Any Real number squared is non-negative.

Therefore, it does not matter what Real value x represents; its square is guaranteed to be zero or more.

In other words, x^2 is obviously greater than -8, for all Real numbers x.

 

[mmm4444bot]

… I understand that [finding the domain of several functions] requires finding the domain of each function and then finding out their intersection …

I'm not sure what you're thinking about intersections, with respect to finding domains of functions. :?

 

[jtw2e2]

Re:

… I understand that [finding the domain of several functions] requires finding the domain of each function and then finding out their intersection …

I'm not sure what you're thinking about intersections, with respect to finding domains of functions. :?

Thanks for clarifying with respect to the problem above. It has been a very long month and these night shifts don't seem to aid in my thinking abilities!

Regarding intersections, our textbook states:

In which the ? symbol indicates an intersection (or elements common in more than one set).

That said, I'm trying to solve this:

If I can understand part (a) above, I think I can do the rest of them.

 

[jtw2e2]

Re: Re:

If I can understand part (a) above, I think I can do the rest of them.

Ok, I was able to get it after all. Ha ha...sorry for the trouble. Thanks again.

 

[mmm4444bot]

You never told us that functions f and g were being combined.

Next time you ask for help, try to give us the complete exercise up-front. Otherwise, we're playing a guessing game.