Why do I receive Error in line 4?

I am getting some error which i am unable to understand:

This line has an error: syms f X Y alpha1 beta1 gamma1 h

Answer 1

[Walter Roberson]

You do not have the Symbolic Mathematics Toolbox installed, but you are using functions that are only present in that toolbox.

[utakarsha mahajan]

Thanks, ill try

[utakarsha mahajan]

I just downloaded and installed the trial version of Matlab on my system. How do I install Symbolic Mathematics Toolbox then??