LogIntegral[z] is the logarithmic integral function li(z).

You can enter complex numbers in Mathematica just by including the constant I, equal to Sqrt[-1]. Make sure that you type a capital I. If you are using notebooks, you can ...

Work with Variables and Functions Work with Lists Work with Rules

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.

Mathematica notebooks provide a sophisticated environment for creating technical documents. But particularly if you want to merge your work with existing material in TeX, you ...

In the standard notebook front end, Mathematica allows you to set a large number of global options. The values of all these options are by default saved in a "preferences ...

When Mathematica cannot give you an explicit result for an integral, it leaves the integral in a symbolic form. It is often useful to manipulate this symbolic form. ...

Mathematical Notation in Notebooks Special Characters Names of Symbols and Mathematical Objects

Ordering in lists. Here is a list of numbers. This gives the elements of t in sorted order.

In some cases you may need to specify pattern sequences that are more intricate than things like x__ or x..; for such situations you can use PatternSequence[p_1,p_2,…]. ...