Notebook History displays a time record of changes made in the input notebook.

EstimatorGains[ss, {p_1, p_2, ..., p_n}] gives the estimator gain matrix for the StateSpaceModel object ss, such that the poles of the estimator are p_i.

NicholsGridLines is an option to NicholsPlot that specifies contours of constant magnitude and constant phase of the closed-loop system.

NyquistGridLines is an option to NyquistPlot that specifies contours of constant magnitude and phase of a closed-loop system.

ObservableModelQ[ss] gives True if the StateSpaceModel object ss is observable, and False otherwise.

PoleZeroMarkers is an option for RootLocusPlot that specifies the markers to be drawn on the complex plane at the open-loop poles, closed-loop poles, and open-loop zeros.

Which[test_1, value_1, test_2, value_2, ...] evaluates each of the test_i in turn, returning the value of the value_i corresponding to the first one that yields True.

When you see a two-dimensional expression on the screen, you can edit it much as you would edit text. You can for example place your cursor somewhere and start typing. Or you ...

There will probably be times when you want to stop Mathematica in the middle of a calculation. Perhaps you realize that you asked Mathematica to do the wrong thing. Or ...

If you use a text-based interface to Mathematica, then the input you give must consist only of characters that you can type directly on your computer keyboard. But if you use ...