Re: repost - expanding inline d[xy]/dx during implicit
- To: mathgroup at smc.vnet.net
- Subject: [mg113179] Re: repost - expanding inline d[xy]/dx during implicit
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sat, 16 Oct 2010 13:13:47 -0400 (EDT)
- Reply-to: hanlonr at cox.net
xy is a separate symbol not the product of x and y. Add a space or an explicit times, i.e., x*y
Bob Hanlon
---- John Accardi <accardi at accardi.com> wrote:
=============
Thanks in advance for any help .....
Implicit Differentiation
Below, I need to get the inline d[xy]/dx to expand in the Dt output.
Ditto for the output of Solve. (I have done other implicit differentiation
calculations that have done this correctly.) What is the issue here?
eq5=x^3-3x^2 y+2xy^2==12
x^3-3 x^2 y+2 xy^2\[LongEqual]12
Dt[eq5,x]
-3 x^2 \[DifferentialD]y/\[DifferentialD]x+3 x^2+4 xy
\[DifferentialD]xy/\[DifferentialD]x-6 x y\[LongEqual]0
Solve[%%,\[DifferentialD]y/\[DifferentialD]x]
{{\[DifferentialD]y/\[DifferentialD]x->(3 x^2+4 xy
\[DifferentialD]xy/\[DifferentialD]x-6 x y)/(3 x^2)}}
*.nb is located here:
http://www.accardi.com/ImplicitDifferentiationForumQueryTest.nb
Thanks,
Gianni