Interval and Parameter

[IHarwell]

There's a relatively quick, somewhat cheeky way to limit the interval to what you want. It basically forces the function to return "NaN" when X>=2.

Instead of {2X if X<2, you could use 2X/(X<2). It works because of how "X<2" works. When X is less than 2, the expression "X<2" evaluates to "1". When it's greater than 2, it evaluates to "0".

In the latter case, it simply makes the whole thing evaluate to "NaN" as you have something over zero.