Because of the sqrt which restricts the domain. Sqrt 1-x^2 = sqrt (1-x)(1+x) basically informs us that the graph cannot exist for real numbers outside of -1<x<1.
Not much atm since it's Friday night, therefore my productivity is very low.
Aware me of your location.
I suppose you could stay just to pick up 3U skills and techniques that may help you in 2U, not necessarily the content itself.
I do know a lot who failed 3U but regret dropping it because 2U is so much easier.
What do you want me to be?
And no he did not.
I'm getting slightly excited. Need time and place now.
Just talk normally, get rid of nervousness. If you don't talk like a retard and sound mildly interesting, you're set.
Oh and that essay, techniques bs etc.