StringReplacePart["string", " snew", {m, n}] replaces the characters at positions m through n in " string" by " snew". StringReplacePart["string", " snew", {{m_1, n_1}, {m_2, ...
StringTake["string", n] gives a string containing the first n characters in " string". StringTake["string", -n] gives the last n characters in " string". StringTake["string", ...
TaggingRules is an option for selections that specifies a list of strings to be associated with a selection.
TextRecognize[image] recognizes text in image and returns it as a string.
Tolerance is an option for various numerical options which specifies the tolerance that should be allowed in computing results.
TransferFunctionFactor[tf] factors the polynomial terms in the numerators and denominators of the TransferFunctionModel object tf.
VarianceEstimatorFunction is an option for LinearModelFit and NonlinearModelFit which specifies the variance estimator to use.
VerifyTestAssumptions is an option to LocationTest and similar functions that controls which assumptions to verify through diagnostic tests.
WindowMargins is a notebook option that specifies what margins to leave around the window that is used to display the notebook on the screen.
The general solution to a differential equation contains undetermined coefficients that are labeled C[1], C[2], and so on. This example has one undetermined parameter, C[1]. ...