Derivatives at a point can be entered using the @ symbol. The location of the derivative is entered in brackets after the @ symbol.
Example:
is entered as d/dx x2 -4 @(x=3)
The @ command is NOT dependent on the derivative being present. It can be used independently of other commands if desired.
Example:
is entered as 4x+1 @(4)
NOTE:
The @ symbol was previously used as an alternative for entering the partial derivative symbol. This use has been deprecated. If you wish to use the partial derivative symbol, you should use the pd command. Any existing equations using the @ symbol will need to be recoded to use pd.