Illustration of Built-in functions and help:

To find out what a specific function does and how to call it, type help and then the name of function. Illustration:

>> help sin

will give a description of sin function.

To call a function, the name of the function is provided followed by the argument(s) which are passed to the function in parentheses. Most of functions then return value(s). For illustration, to find the absolute value of -4, the expression below would be entered:

>> abs(-4)

that is a call to the function abs. The parentheses number, the -4, is the argument. The value 4 would then be returned as an outcome.