 
 
 
23.2.1  Approximating derivatives
The nDeriv
command numerically approximates the value of a derivative.
- 
nDeriv takes as arguments:
- 
expr, expression.
- Optionally, x, the variable used in the
expression (by default x).
- Optionally, h (by default 0.001).
 
- nDeriv(ex ⟨,x,h ⟩)
returns an approximated value of the derivative of the expression
ex at the point x using the formula:
For a more general command on numeric differentiation, see Section 13.2.4.
Examples
|  | | |  | ⎛ ⎝
 | ⎛ ⎝
 | x+0.001 | ⎞ ⎠
 | 2− | ⎛ ⎝
 | x−0.001 | ⎞ ⎠
 | 2 | ⎞ ⎠
 | · 500.0 | 
 |  |  |  |  |  |  |  |  |  |  | 
 | 
| nDeriv(exp(x^2),x,0.00001) | 
| subst(exp(nDeriv(x^2,x,0.00001)),x=1) | 
which is an approximate value of e2≈ 7.38905609893.
 
 
