# Math question... kinda abstract

• 05-11-2003
ygfperson
Math question... kinda abstract
Do all expressions have a domain? Or is it just for functions?
• 05-11-2003
doubleanti
yes all expressions have a domain.
• 05-11-2003
ygfperson
Why?
• 05-11-2003
doubleanti
oh, whoops should have explained...

well, functions are merely shorthand notations for longer expressions, and since functions have domains (be they the whole complex plane, only real parts, subsets of it due to singularities, etc), expressions do as well.
• 05-12-2003
Shiro
A function is a mapping of one set on another set, like f:A->B. The first set is the domain, so each function has a domain.
• 05-12-2003
Brian
Quote:

Originally posted by doubleanti
oh, whoops should have explained...

well, functions are merely shorthand notations for longer expressions, and since functions have domains (be they the whole complex plane, only real parts, subsets of it due to singularities, etc), expressions do as well.

Woah, woah, hold on there! You sure that isn't a quote from star trek?

I feel incredibly stupid whenever da talks, moreso than usual.
• 05-12-2003
confuted
"The whole complex plane" would mean all numbers, real, imaginary, and complex (combination of the two)

"Only real parts" would mean part of the real numbers (you know...the ones represented by your fingers and toes.

By "singularities," I believe he means holes, such as the one found in y=(x^2)/(x-2) at x=2.

So...no star trek, just some combination of pre-calc and calc class.
• 05-12-2003
ygfperson
Quote:

"Only real parts" would mean part of the real numbers (you know...the ones represented by your fingers and toes.
Or parts thereof.