List of derivatives?
06-13-2018, 10:28 AM
Post: #1
 DrD Senior Member Posts: 1,124 Joined: Feb 2014
List of derivatives?
The command, "diff(expr, var, [Order])," is designed to return derivatives of a specified order; but [Order] does not support a {list} as an argument for the Order option. Is there a convenient way to obtain a list, (or a range), of the derivatives of an expression? (This might be useful for identifying patterns in a series, etc.).

[CAS] Example:
f(x):=ln(x)
; // ==> {x^-1, -1* x^-2, 2*x^-3 }, With the first three derivatives as the desired "Order."

f'(x);
f''(x);
f'''(x);

-or-

diff(f(x),x,1);
diff(f(x),x,2);
diff(f(x),x,3);

Objective: Obtain a list of the derivatives of an expression from a single command.

Thanks!

-Dale-
06-13-2018, 11:26 AM (This post was last modified: 06-13-2018 11:32 AM by Didier Lachieze.)
Post: #2
 Didier Lachieze Senior Member Posts: 1,169 Joined: Dec 2013
RE: List of derivatives?
(06-13-2018 10:28 AM)DrD Wrote:  Objective: Obtain a list of the derivatives of an expression from a single command.

map([1,2,3],j->diff(f(x),x,j))
or
apply(j->diff(f(x),x,j),[1,2,3])
06-13-2018, 01:23 PM
Post: #3
 DrD Senior Member Posts: 1,124 Joined: Feb 2014
RE: List of derivatives?
Very nice! Thanks, Didier!

-Dale-
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