Re[z] gives the real part of the complex number z.

lhs := rhs assigns rhs to be the delayed value of lhs. rhs is maintained in an unevaluated form. When lhs appears, it is replaced by rhs, evaluated afresh each time.

SetSharedFunction[f_1, f_2, ...] declares the symbols f_i as shared functions whose downvalues are synchronized among all parallel kernels.

SortBy[list, f] sorts the elements of list in the order defined by applying f to each of them.

Subsets[list] gives a list of all possible subsets of list. Subsets[list, n] gives all subsets containing at most n elements. Subsets[list, {n}] gives all subsets containing ...

Ticks is an option for graphics functions that specifies tick marks for axes.

ToDiscreteTimeModel[sys, \[Tau]] gives the discrete-time approximation with sampling period \[Tau] of the continuous-time StateSpaceModel or TransferFunctionModel object ...

If you have a list of elements, it is often important to be able to apply a function separately to each of the elements. You can do this in Mathematica using Map. This ...

When you make a definition in the form f[args]=rhs or f[args]:=rhs, Mathematica associates your definition with the object f. This means, for example, that such definitions ...

There are many situations where one wants to find a formula that best fits a given set of data. One way to do this in Mathematica is to use Fit. Basic linear fitting. Here is ...