Solving Polynomial Functions: Find x in 0<|x|≤1/2

mtayab1994
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Homework Statement



f:ℝ→ℝ
x:→sqrt(x^2+1)-lxl

Homework Equations



calculate f^-1(]0,1])

The Attempt at a Solution



well i chose a y from ]0,1] and tried to find an x that solves the problem like the following.

0<sqrt(x^2+1)-lxl≤1

at the end i got the following: 0<lxl≤1/2 is my work correct?
 
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No it is not correct. What is your work??
 
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