On 14 November 2014 13:18, Ondřej Čertík <ondrej.cer...@gmail.com> wrote: > > On Nov 14, 2014 8:57 AM, "Bill Page" <bill.p...@newsynthesis.org> wrote: >> >> It seems to me that we should forget about x and y. All we really need is >> >> |z|' = d |z| / d z = conjugate(z) / (2*|z|) >> >> and the appropriate algebraic properties of conjugate. > > Sure, we can make a CAS return this. But then you get the 1/2 there. >
Yes. >> ... >> The constant 1/2 is irrelevant. > > Well, but how do I recover the real derivative from the complex one if they > differ by a factor of 1/2? > What do you mean by "the real derivative"? Perhaps we can just define that as d f / d z + d f / d conjugate(z) > In other words, what is the utility of such a definition then? > > I can see the utility of differentiating with respect to x, as at least you > must recover the real derivative results. > You are not differentiating with respect to x, you are differentiating with respect to (z+conjugate(z))/2 Bill. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
