Posted by Kennedy on Monday, December 15, 2008 at 3:30pm.
how do i know what the domain is in these problems...
i know that domain is the x value but how can i tell what it is?
y=1/x
y=3/x^249
y{x}
y=square root of 3x
y=[x].

Math  Reiny, Monday, December 15, 2008 at 4:37pm
in plain English, the domain is the value of x that you may use in your given function to return a value
in your first one, remember that we cannot divide by zero, so x=0 is the only value which would not work
so the domain would be the set of real numbers, except x is not equal to zero
for your second, y = 3/(x^249)
the trouble arises when x = ± 7
do you think you can state the domain?
another case where difficulty arises is when your function tries to take the square root, (or any even root) of a negative number.
e.g. your third one:
y = √(3x)
your domain would be all real values of x which would make (3x) ≥ 0 
Math  Kennedy, Monday, December 15, 2008 at 4:45pm
i have a question.... when i get a function, how do i konw if it has an inverser... for example, y=ab.solute value x, then 2. i plugged in x=ab.solute val. of y, then 2. but how do i know if that is an inverse??