Re: How to plot derivative directly?
- To: mathgroup at smc.vnet.net
- Subject: [mg118106] Re: How to plot derivative directly?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Tue, 12 Apr 2011 05:59:23 -0400 (EDT)
f[x_] = x^3 - 6 (x + 1)^2 + x - 7;
Plot[f'[x], {x, -3, 8}]
Attributes[Plot]
{HoldAll, Protected}
Plot[Evaluate[D[f[x], x]], {x, -3, 8}]
Bob Hanlon
---- "=C5 er=C3=BDch Jakub" <Serych at panska.cz> wrote:
==========================
Dear mathgroup,
it seems to me, that response to my question shall be very simple,
but I cannot find it. :-(
I want to plot the derivative of the function. I would like to do it
directly, something like:
Plot[D[x^3 - 6 (x + 1)^2 + x - 7, x],{x,-3,8}]
It returns: General::ivar: "-2.99978 is not a valid variable."
I can understand that it is because local variable x from Plot command
interferes with the x variable from the D[].
Yes I can bypass the problem by:
deriv = D[x^3 - 6 (x + 1)^2 + x - 7, x]
Plot[deriv, {x, -3, 8}]
which is fully functional, but as far as I know Mathematica, there must
be some simple solution how to do it directly inside the Plot[].
Thanks in advance for kick-off
Jakub