I have 2 functions, f(x) and g(x), the domain of f(x) is negative infinity to 3. The domain of g is that x cannot equal zero. When adding the functions, how do I state the domain taking the above into account?

Question

I have 2 functions, f(x) and g(x), the domain of f(x) is negative infinity to 3.  The domain of g is that x cannot equal zero.  When adding the functions, how do I state the domain taking the above into account?

caominhim · Answer

the new domain is the intersection of the previous 2 domains

anonymous · Answer

Thank you for that, I thought that was the case but was not 100% sure :)  Should I just write as intersection of the sets or state the intersection?

caominhim · Answer

there's another rule for division though, you can't include numbers that would make the denominator 0

write the actual intersection, i'm sure your teacher wants you to actually find it and not write "the intersection of the two domains"

caominhim · Answer

btw i just relearned this by googling it http://www.mathsisfun.com/sets/functions-operations.html

anonymous · Answer

Thank you so much for your help :)