When you define a complicated function, you will often want to let some of the arguments of the function be "optional". If you do not give those arguments explicitly, you ...

In many practical situations it is convenient to consider limits in which a fixed amount of something is concentrated into an infinitesimal region. Ordinary mathematical ...

 

Mathematica has a very general notion of functions, as rules for arbitrary transformations. Values for variables are also assigned in this manner. When you set a value for a ...