How to Maximize the Variable within given bounds

How would one go about finding the largest number x (one significant digit is enough) such that the numerical evaluation of expression (1 + x) − 1 equals to zero.

I need to show that MatLab gives strange answers sometimes (thanks to Floating-point arithmetic).

Answer 1

[Walter Roberson]

x = eps(1/2)

[Benjamin Halkowski]

Thank you, but is there anyway to have MATLAB spit out this infinitesimal amount while solving for the linear function above?