Hrm. I don't understand. It should definitely be (| j. 1:), not (] j. 1:).

The idea is that you're taking a line with length (%: n) and using it to
construct a line with length (%: n+1).

So for example, the distance (|) from 0j0 to 1j1 is (%: 2).

Now you want to make a right triangle whose sides are 1 and (%:2), so that
the hypotenuse is (%: 3).

If you used ] instead of | on 1j1, you'd wind up at 1j.2, instead of
1.41421j1, and that doesn't work:


   *:| ( | 1j1) j. 1 NB. what i want

3

   *:| ( ] 1j1) j. 1 NB. not what i want. :)

5



Like I said, I probably just didn't explain it very well. :)








On Sun, Feb 28, 2016 at 1:50 AM, Linda A Alvord <[email protected]>
wrote:

> Michal, Your original post had | which you meant as ]
>
> Here is how I got to Kip's final result. He mentioned   you needed to add 1
>
>
>
>  f=: 13 :' 1 + *:@|A=: (]j.1:)^:(<y) 0j1'
>
>    f 10
>
> 2 5 10 17 26 37 50 65 82 101
>
>    A
>
> 0j1 0j2 0j3 0j4 0j5 0j6 0j7 0j8 0j9 0j10
>
>    |A
>
> 1 2 3 4 5 6 7 8 9 10
>
>    *:|A
>
> 1 4 9 16 25 36 49 64 81 100
>
>    g=: 13 :' 1 + *:|0 j.1 + i.y'
>
>    (f 10)-:g 10
>
> 1
>
>    5!:4 <'f'
>
>       ┌─ 3
> ── : ─┴─ ,:' 1 + *:@|A=: (]j.1:)^:(<y) 0j1'
>
>    5!:4 <'g'
>
>   ┌─ 1
>   ├─ +
> ──┤   ┌─ [:
>   │   ├─ *:
>   └───┤    ┌─ [:
>       │    ├─ |
>       └────┤    ┌─ 0
>            │    ├─ j.
>            └────┤    ┌─ 1
>                 └────┼─ +
>                      └─ i.
>
>    f
>
> 3 : ' 1 + *:@|A=: (]j.1:)^:(<y) 0j1'
>
>    g
>
> 1 + [: *: [: | 0 j. 1 + i
>
>
>
>
>
> I tend to write most code in an explicit fashion and then see the J
> translation.
>
>
>
> Linda
>
>
>
> -----Original Message-----
> From: Programming [mailto:[email protected]] On
> Behalf Of Michal Wallace
> Sent: Friday, February 26, 2016 3:17 PM
> To: [email protected]
> Subject: Re: [Jprogramming] Imaginary Squares
>
>
>
> Er... I guess I didn't explain that as clearly as I thought.
>
>
>
> The first diagonal (| 1j1) has length (%:2).
>
>
>
> The idea was to rotate this segment down to the real line and then make
> another right triangle by drawing the line up to ((%:2) j. 1).
>
> Pythagoras tells us the hypotenuse of this triangle is (%: +/ *: (%2), 1)
> which is (%: +/ 2 1) or (%: 3).
>
>
>
> So basically it's just generating the square roots of each natural number
> in turn, and then you just square those to get the area.
>
>
>
> The line at the end was actually the answer:
>
>
>
>    *:@| (|j.1:)^:(<n) 0j1 [ n=. 10
>
> 1 2 3 4 5 6 7 8 9 10
>
>
>
> Not really a puzzle. I just thought it was cool. :)
>
>
>
>
>
>
>
> On Fri, Feb 26, 2016 at 1:51 PM, Kip Murray < <mailto:
> [email protected]> [email protected]> wrote:
>
>
>
> >    areas =: 1 + [: *: 1 + i.
>
> >    areas 10
>
> > 2 5 10 17 26 37 50 65 82 101
>
> >
>
> > --Kip Murray
>
> >
>
> > On Friday, February 26, 2016, Michal Wallace
>
> > < <mailto:[email protected]> [email protected]>
>
> > wrote:
>
> >
>
> > > Imagine a compass rooted at the origin of the complex plane.
>
> > >
>
> > > Starting at the point 0j1, draw the arc down to the real line, and
>
> > > then from this point, draw vertical line segment extending upwards 1
>
> > > unit, to arrive at the point 1j1.
>
> > >
>
> > > Repeat this process of drawing the arc down to the real line and
>
> > > moving
>
> > up
>
> > > 1 unit N times, creating a series of points along the horizontal
>
> > > line  (] j. 1:).
>
> > >
>
> > > For each point, draw a line segment from the origin to the point,
>
> > > and
>
> > then
>
> > > draw a square (*:) whose sides are the length (|) of this segment.
>
> > >
>
> > > What is the area of each square?
>
> > >
>
> > >     *:@| (|j.1:)^:(<n) 0j1 [ n=. 10
>
> > > --------------------------------------------------------------------
>
> > > -- For information about J forums see
>
> > >  <http://www.jsoftware.com/forums.htm>
> http://www.jsoftware.com/forums.htm
>
> >
>
> >
>
> >
>
> > --
>
> > Sent from Gmail Mobile
>
> > ----------------------------------------------------------------------
>
> > For information about J forums see  <http://www.jsoftware.com/forums.htm>
> http://www.jsoftware.com/forums.htm
>
> ----------------------------------------------------------------------
>
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> http://www.jsoftware.com/forums.htm
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