Partial differentiation

[Serene Chan]

Dear all,

may i know whether i can partial differentiate a multi-variable (say
x, y , z) with respect to x first, then y then z, using matlab?

how do i get it worked out?

Thanks for help..

Shi Yun

[martin alain]

dear serene,
i answer because i want help you :
use the partial derivative toolbox, or symbolic toolbox.
You can compute the derivatives with use the mathematic definition,
or compute the numeric limit lim (h->0) (f(x+h)-f(x))/h.
With classics functions, order of derivative doesnt matter (operator
derivative commute, ouf!)
Alain

[Ray]

Dear Alain,

i get a problem that i cant find out the partial derivative toolbox
of matlab.
and my version is 6.5

[Carlos Lopez]

Hello Serene:
What is precisely what you want to produce?:
a) the first order explicit (analytic) derivatives of a known
function
b) the numeric version of a)
c) the third order derivative of an analytic function?
d) the numeric version of c)
e) other option
The solutions differ for each case. For a) or c) you need symbolic
computations. For b) and/or d) there exist other solutions within
matlab, either numerically exact or just approximated. However, there
exist more solutions for b) rather than d) (with a given accuracy)
Do you really need the analytic solution?
Regards
Carlos