$SoundDisplayFunction gives the default setting for the option DisplayFunction in sound functions.

$SystemWordLength gives the effective number of bits in raw machine words on the computer system where Mathematica is running.

Symbolic Computation Values for Symbols Transforming Algebraic Expressions

Differentiation Total Derivatives Derivatives of Unknown Functions

Introduction Linear Optimization Numerical Nonlinear Local Optimization

Introduction Exploring Data Formats Interactively Obtaining Data Formats Programmatically

Function Names as Expressions Applying Functions Repeatedly Applying Functions to Lists and Other Expressions

NDSolve returns solutions as InterpolatingFunction objects. Most of the time, simply using these as functions does what is needed, but occasionally it is useful to access the ...

There are many situations where you want to write a particular algebraic expression in the simplest possible form. Although it is difficult to know exactly what one means in ...

"How to" Topics Global Aspects of Mathematica Sessions The Internals of Mathematica