Re: A question on Newton's Method

"Jon Harrop" <usenet@xxxxxxxxxxxxxx> wrote in message
news:42503d87$0$42333$ed2619ec@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx

> Really? Have you considered the Fortran equivalent of my numerical
analysis
> example? How about some other examples? Can you design a single example of
> numerical analysis which is more comprehensible in Fortran?

Please submit your equivalent of

http://home.comcast.net/~kmbtib/conv2b.f90

in the non-Fortran language of your choice!

> > f[x_] := x^3-x-1
> > fp[x_] := D[f[x],x]
> > Plot[fp,{x,-1,2}]

> Of course not, it's wrong.

> Firstly, there's no point in defining fp[x] when you can just use f'[x].
> Secondly, you need to give the plot function an expression to plot, not a
> function. So you want:

> Plot[f'[x], {x, -1, 2}]

No, I don't want this! In ordinary everyday mathematical usage,
you can define a new function to be the derivative of an old
function. For example, psi(x) = (d/dx)(ln(Gamma(x))). We want
to be able to do this in Mathematica; I don't want to keep
referring to the original function (as in your f'[x] above.) So
the original example should have been changed to:

> > f[x_] := x^3-x-1
> > fp[x_] := D[f[x],x]
> > Plot[fp[x],{x,-1,2}]

When you finally figure out how to make this work you will
have an excellent example of the true horror of Mathematica!

--
write(*,*) transfer((/17.392111325966148d0,6.5794487871554595D-85, &
6.0134700243160014d-154/),(/'x'/)); end


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