Directional Derivative

01292015, 12:17 PM
(This post was last modified: 02052015 07:01 PM by salvomic.)
Post: #1




Directional Derivative
hi all,
would like anybody to help me to get a program for Directional Derivative? Starting with this: it's the dot product between Gradient of v and person of u, ( {tex} \( \bigtriangledown f \cdot \overrightarrow{v} \) {/tex} ) so dot (grad(u) , v/normalize(v)) could be good, but if use it with "Define" it doesn't works, as "dot" (lowercase) is always changed in "DOT" (uppercase) and the function gives error "dot vector Error: bad argument value"... (I'm using CAS) Thank you in advance! Salvo 

01292015, 04:36 PM
(This post was last modified: 02052015 07:02 PM by salvomic.)
Post: #2




RE: Directional Derivative
I'm trying this program:
Code:
It seems to works with f as a function (expression), f(0), like (x^2x*y) and v as vector (also not normalized), like [3,4] or [x,3y]; the program first normalize the vector finding its versor, and then return the symbolic directional derivative in the direction of that vector... Any help to make it better? There is a way to have the function listed in the Toolbox > User? Thank you :) salvo 

01292015, 06:57 PM
Post: #3




RE: Directional Derivative
(01292015 04:36 PM)salvomic Wrote: There is a way to have the function listed in the Toolbox > User? Make a nonCAS wrapper. DDER(f,v) BEGIN derivdir(f,v); END; Since DDER is a nonCAS program, you would then have to enter your arguments as strings: DDER("x^2*y+z","[3,4,1]"); Graph 3D  QPI  SolveSys 

01292015, 07:08 PM
Post: #4




RE: Directional Derivative  
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