how to solve piece-wise function?

f(x)= {1 if x>=0, 0 if x=0, -1 if x<=0

[Guillaume]

Note that your function is ill-defined for x == 0, since it passes all three conditions. You should use strict comparison, < instead of <=.

[rising falcon]

thak you

Answer 1

[Guillaume]

That function has a name, it's the signum function, called sign in matlab.

I'm not sure what you mean by solve. The roots of that function is obviously just 0.

[rising falcon]

how to wirte it in matlab?why we use if and end statement to write it in matlab?

[Guillaume]

How to write functions and how to use if statement is covered in the Getting Started tutorial in the doc and in million of other tutorials.

function s = mysignum(x)
  if x > 0
    s = 1;
  elseif x < 0
    s = -1;
  else
    s = 0;
  end
end