"How to" Topics Files, Streams, and External Operations Importing and Exporting

Finding the date and time. This gives the current date and time. The Mathematica DateList function returns whatever your computer system gives as the current date and time. ...

You can define the derivative in Mathematica of a function f of one argument simply by an assignment like f'[x_]=fp[x]. This defines the derivative of f(x) to be fp(x). In ...

There are many functions that are built into Mathematica. This tutorial discusses how you can add your own simple functions to Mathematica. As a first example, consider ...

If you make a definition such as f[x_]:=value, Mathematica will use the value you give for any f function it encounters. In some cases, however, you may want to define a ...

Just as Mathematica allows you to define how expressions should be evaluated, so also it allows you to define how expressions should be formatted for output. The basic idea ...

When you do long calculations, it is often convenient to give names to your intermediate results. Just as in standard mathematics, or in other computer languages, you can do ...

You can define wavelets to plug into the wavelet analysis framework by using the correct template. A wavelet wave is of the form wfam[args], where wfam is the symbol that ...

Integration functions. Here is the integral ∫_a^bx^2 dx. This gives the multiple integral ∫_0^adx ∫_0^bd y(x^2+y^2).

Density and contour plots. This gives a density plot of sin(x) sin(y). Lighter regions show higher values of the function. Some options for DensityPlot.