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