1. f(x) = (x+2)/(x^2 -4)
2. f(x) = (2x+1)/(sqrt x+4)
So if I'm doing this right, then I got (-inf,2] for the first one, and [-4,inf) for the second. But, that's just looking at a graph. So now how would you find these answers (if they are correct that is) by not looking on a graph. Is there some algebraic way of doing this? My textbook isn't helping me much with this kind of question.
Also as a side question; am I doing the interval notation correctly?
But see how do you know that? Is it just something that after a while you know when you see it? I know that polynomials are always continuous, but rational functions, do you just plug some numbers in? I know this is probably a silly problem, but I've always had troubles understanding things related to domains.