MATLAB: Relational operator == doesn’t work properly in some cases!

Question

When I run this code:

1.1-1==0.1

I recieve this:

ans =
  logical
   0

I think it's not rational. Could somebody explain why I'm getting that result?

Answer 1

You are seeing the effects of floating-point approximation error.

See for example: Why is 0.3 - 0.2 - 0.1 (or similar) not equal to zero? and Floating-Point Numbers.