LocatorAutoCreate is an option for LocatorPane, Manipulate, and related functions that specifies whether new locators should be created when clicking away from existing ...

Off[symbol::tag] switches off a message, so that it is no longer printed. Off["name"] switches off a named group of messages.Off[s] switches off tracing messages associated ...

--x decreases the value of x by 1, returning the new value of x.

++x increases the value of x by 1, returning the new value of x.

TransformationFunctions is an option for Simplify and FullSimplify which gives the list of functions to apply to try to transform parts of an expression.

Unique[] generates a new symbol, whose name is of the form $nnn. Unique[x] generates a new symbol, with a name of the form x$nnn. Unique[{x, y, ...}] generates a list of new ...

Write[channel, expr_1, expr_2, ...] writes the expressions expr_i in sequence, followed by a newline, to the specified output channel.

$ContextPath is a global variable that gives a list of contexts, after $Context, to search in trying to find a symbol that has been entered.

$Path gives the default list of directories to search in attempting to find an external file.

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 ...