Numerical Derivative

Press to view the calculus menu, then to select numerical differentiation, nDer.

The syntax is: nDer( expression,variable [,value] )

The numerical derivative option approximates the first derivative of expression with respect to variable at value. If value is omitted, the current value of variable is used.

Note: The value of the derivative is found by computing the slope of the line through the points ( value- , f(value-) ) and ( value+ , f(value+) ) for some very small number .

The value of can be changed in the tolerance editor available by pressing . typically has a value of about 0.0001.

Though this method is less accurate than der1, it can be used to evaluate any expression, including a single nesting of itself for calculating the second derivative.