How do I create conditional statements in Symbolic Math Toolbox 3.1.3 (R14 SP3)?

I would like to create a discontinous, conditional, symbolic function in MATLAB. When I try to use > (or <) I get the following error:

 ??? Function 'gt' is not defined for values of class 'sym'.

Answer 1

[MathWorks Support Team]

The ability to perform conditional operations is not available in Symbolic Math Toolbox 3.1.3 (R14 SP3). Boolean logic is available in the Extended Symbolic Math Toolbox 3.1.3 (R14 SP3).

Conditional operation can be approximated using the Symbolic Math step function, HEAVISIDE. Please note that the HEAVISIDE function returns NaN for heaviside(0), and so the resultant symbolic function is not defined for every value.