# the term "same" in math

##### Full Member
Also can I say that same means "doesn't matter which once to use of the two equal variables, they are the same" ?!

#### lev888

##### Full Member
Also can I say that same means "doesn't matter which once to use of the two equal variables, they are the same" ?!
Once again, example would help.

x = y means the 2 variables have the same value.

#### HallsofIvy

##### Elite Member
"x= y" means that "x" and "y" are two symbols both representing the same number ("same" here having its usual English meaning). Some times you will see "same" used to mean that two things are "equivalent" under a previously define equivalence relation.

#### JeffM

##### Elite Member
We have said before that what "same" means depends on context. In elementary algebra, it generally means that two sets of symbols represent the same numeric value.

$$\displaystyle 3 + 7 = (2 * 9) - 8.$$

In other branches of mathematics, it may have a different meaning

$$\displaystyle f'(x) = g'(x)$$

means that two functions have equivalent derivatives, which are functions rather than numbers.

What it always means, however, is that you can replace what is on one side of the equality with what is on the other whenever that is convenient.

And whatever do you mean by "cosmetics?" The primary meaning of that word refers to things like lipstick and fingernail polish.