what is the inverse of y=x^2? and is it a function? what restrictions are placed in the inverse of y=x^2 to make it an inverse?

Question

anonymous · Answer

HELP PLEASE!

accessdenied · Answer

If you switch the y and x and solve for x...
  y = x^2 <=> x = y^2
                       sqrt(x) = |y|
                       +- sqrt(x) = y

This is not one, but two functions.

accessdenied · Answer

solve for y, rather

anonymous · Answer

Thankyou for your help :)
I understand it now!

accessdenied · Answer

No problem!  You also understand the restriction part?

anonymous · Answer

not really :/

accessdenied · Answer

Well, if we restricted the domain (our x-values) of our original function to be only positive real numbers and 0, we'd get this half of the parabola:
|dw:1330948570626:dw|

Since we no longer have the other half of the graph, this satisfies the horizontal line test.