# Very simple applications' issue

1. Nov 3, 2012

### Andrax

1. The problem statement, all variables and given/known data
so i want to prove that an application is bijective
y $\geq$ 1we're looking for an x$\geq$-2 : y= f(x)
anyway at the end
i have lx+2l=$\sqrt{}y+1$
the teached said x = $\sqrt{}y+1$-2 without studying the other case
Ps: the +1 is includedi nthe square root
2. Relevant equations

3. The attempt at a solution
the other case lx+2l=$\sqrt{}y+1$
x+2=$\sqrt{}y+1$ or x+2=-$\sqrt{}y+1$

the second x is going to be <2 so we can exclude it the first x is going to be >2 we're oging to use it , but why our teacher didn't study the second case in which x+2 = -$\sqrt{}y+1$ ?

Last edited: Nov 3, 2012
2. Nov 3, 2012

### Staff: Mentor

Your LaTeX is broken, so I can't understand what you have attempted to write.