[1] enter (in console) ; [2] implicit functions

On 09/28/2012 05:04 PM, Stavros Macrakis wrote:
> (%i27) y + log(y) + x = 0;
> (%o27) log(y)+y+x=0
> (%i28) diff(%);
> (%o28) (1/y+1)*del(y)+del(x)=0
> (%i29) ratsubst(dydx,del(y)/del(x),%);   <<< doesn't always produce 
> 'clean' result, but does in this case
> (%o29) (((dydx+1)*y+dydx)*del(x))/y=0
> (%i30) solve(%,dydx);
It might be interesting for Ivo to know another way to do the same thing 
done above:

(%i1) depends (y, x);

(%o1)                        [y(x)]

(%i2) diff (y + log(y) + x = 0, x);

                          dy

                          --

                          dx   dy

(%o2)                    -- + -- + 1 = 0

                          y    dx

(%i3) solve(%, diff(y,x));

                           dy       y

(%o3)                    [-- = - -----]

                           dx     y + 1


Regards,
Jaime