1. your syntax is wrong.
2. your equation cancels out.
solve does not expect [A=B]=0.
Try solve(A=B, 'diff(y,x,2));
After correction, there is no solution because 'diff(y,x,2) cancels...
_____
From: maxima-bounces at math.utexas.edu [mailto:maxima-bounces at math.utexas.edu]
On Behalf Of Ronald Modesitt
Sent: Sunday, June 08, 2008 2:40 PM
To: maxima at math.utexas.edu
Subject: Implicit differentiation question
All,
This is really more a Maxima procedure question than one about implicit
differentiation. I would like to solve for d^2y/dx^2 ind the following
equation.
(%i1) eqn:x^2+y^2=r^2;
(%o1) y^2+x^2=r^2
(%i2) depends(y,x);
(%o2) [y(x)]
(%i3) d1:diff(eqn,x);
(%o3) 2*y*('diff(y,x,1))+2*x=0
(%i4) solve(d1,'diff(y,x));
(%o4) ['diff(y,x,1)=-x/y]
(%i5) d2:diff(eqn,x,2);
(%o5) 2*y*('diff(y,x,2))+2*('diff(y,x,1))^2+2=0
(%i6) subst(%o4,'diff(y,x),%o5);
(%o6)
[2*y*('diff(y,x,2))+2*('diff(y,x,1))^2+2=2*y*('diff(y,x,2))+(2*x^2)/y^2+2]=0
(%i7) solve(%o6,'diff(y,x,2));
(%o7) []
I suspect my syntax in %i7. I appreciate the help
Ron