solve: (x^x)=2*x

JVERSION

Engine: j901/j64avx2/windows

Release-e: commercial/2020-01-29T11:17:19

Library: 9.01.18

Qt IDE: 1.8.5/5.12.6

Platform: Win 64

Installer: J901 install

InstallPath: c:/users/skip/j901

Contact: www.jsoftware.com


load 'math/calculus'


Newton =: adverb : ']-u%(u deriv_jcalculus_ 1)'(^:_)("0)


(^~ - +:) Newton 2

2

(^~ - +:) Newton 1

0 NB. Something wrong here!

]x=.(^~ - +:) Newton 0.2

0.346323

   (x^x)  = 2*x
1                           NB.  x= 0.346323 is Correct!

]x=.(^~ - +:) Newton 1.1

0.346323j1.2326e_32


(x^x)= 2*x

1 NB. This also works. (within tolerance limit)


Skip Cave
Cave Consulting LLC


On Thu, Feb 6, 2020 at 9:59 AM Henry Rich <henryhr...@gmail.com> wrote:

> 1. Choose a different starting guess
>
> 2. Update the addon
>
> Henry Rich
>
> On 2/6/2020 10:36 AM, Brian Schott wrote:
> > Henry et al,
> >
> > I have 2 questions.
> >
> > How would the second root at 2 be found with Skip's problem?
> > Why do I get the following error?
> >
> > server:~ brian$ /Users/brian/j901/bin/jconsole ; exit;
> >     JVERSION
> > Engine: j901/j64avx/darwin
> > Release-c: commercial/2020-01-11T12:22:31
> > Library: 9.01.20
> > Platform: Darwin 64
> > Installer: J901 install
> > InstallPath: /users/brian/j901
> > Contact: www.jsoftware.com
> >     load'math/calculus'
> >     Newton =: adverb : ']-u%(u deriv_jcalculus_ 1)'(^:_)("0)
> >     (^~ - +:) Newton 0.5
> > |domain error: deriv_jcalculus_
> > |       13!:8(3)
> >
> > Thanks,
> >
> > On Wed, Feb 5, 2020 at 7:34 AM Henry Rich <henryhr...@gmail.com> wrote:
> >
> >> I misread your function.
> >>
> >>      (^~ - +:) Newton 1.1
> >> 0.346323j1.2326e_32
> >>      (^~ - +:) Newton 0.5
> >> 0.346323
> >>
> >> Still need those guardrails!
> >>
> >> Henry Rich
> >>
> >> --
> > (B=)
> > ----------------------------------------------------------------------
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>
> ----------------------------------------------------------------------
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