I am uncomfortable with this reasoning, because: *) i:9j3 is related to complex arithmetic only by notation.
*) class becomes boring when its pace is set for someine else (when it does not match the student's needs). *) simplicity is good, but so are different perspectives. Waiting to introduce imaginary numbers before introducing this notation seems analogous to waiting to introduce polynomials before introducing decimal numbers. Anyways, I this notation can be optional, but if I were stuck teaching a class using J (rather than providing guidance, pacing and structure to a group of students who had been taught how to learn and who were being responsible for their own education) I think I'd introduce this as an optional notation about the same time I introduced i: -- Raul On Tuesday, January 15, 2013, Linda Alvord <[email protected]> wrote: > Devon, Since I think of everything going forward from kindergarten (maybe > someday we'll do more with prenatal education) I would use Y=: _2 + 0.5 * > i.9" until the middle of the second year of algebra. > > I really like your solution! It would be a great next step when teaching > imaginary numbers. > > Linda > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Devon > McCormick > Sent: Monday, January 14, 2013 2:58 PM > To: J-programming forum > Subject: Re: [Jprogramming] atop continues to puzzle me > > Linda - > > a nice short cut for your expression "Y=: _2 + 0.5 * i.9" is "Y=: i:2j8". > In general, providing the complex argument PjN to i: gives you N+1 points > from -P to P. > > Regards, > > Devon > > > On Mon, Jan 14, 2013 at 12:24 PM, Jose Mario Quintana < > [email protected]> wrote: > >> To Henry: >> >> My apologies, the worst part is that I noticed the misspelling but I >> neglected to correct it; I guess watching the playoffs and writing to >> the forum do not mix very well. >> >> To Linda: >> >> That is a nice feature; thanks for sharing it. One refreshing thing >> about J is that one never seems to stop learning it. Moreover, if one >> follows the forums and this one in particular one is shown (or >> reminded) how capable the J system really is. >> >> On Mon, Jan 14, 2013 at 3:10 AM, Linda Alvord >> <[email protected]> >> wrote: >> > Jose, Here's a simper version. Using the aspect ratio helps make the >> > derivative more obvious. I use Chrome and I don't know how this >> > will >> look >> > elsewhere. >> > >> > Load 'plot' >> > u=: -: >> > v=: *: >> > Y=:_2 + 0.5 * i.9 >> > f=: 13 :'(] ; [:|:u@v d._2 _1 0 1 2 )y' >> > f >> > plot f Y >> > 'aspect 1'plot f Y >> > >> > Linda >> > >> > -----Original Message----- >> > From: [email protected] >> > [mailto:[email protected]] On Behalf Of Linda >> Alvord >> > Sent: Sunday, January 13, 2013 9:21 PM >> > To: [email protected] >> > Subject: Re: [Jprogramming] atop continues to puzzle me >> > >> > load'plot' >> > >> > u=: -: >> > v=: *: >> > Y=: _2 + 0.01 * i.401 >> > f=: 13 :'(] ; [:|:u@v d._2 _1 0 1 2 )y' >> > f >> > ] ; [: |: u@v d._2 _1 0 1 2 >> > plot f Y >> > >> > If this is in a jijs and then run, it will shw the graph you >> > expect bu >> t >> > it will provide a long J error message in a separate window. I >> > don't >> know >> > how to prevent it. >> > >> > Also, maybe when u@v can be replaced by ([:u v)"v that will work >> also. >> > >> > Linda >> > >> > >> > -----Original Message----- >> > From: [email protected] >> > [mailto:[email protected]] On Behalf Of Jose >> Mario >> > Quintana >> > Sent: Sunday, January 13, 2013 5:17 PM >> > To: [email protected] >> > Subject: Re: [Jprogramming] atop continues to puzzle me >> > >> > To Raul: >> > >> >> I have no idea what "works reasonably well" means. >> > >> > That is a very subjective statement, apparently one can make use of >> > (@) and (@:) within the scope of (d.) but, of course, that depends >> > on >> one's >> > point of view. >> > >> >> But consider also: >> >> >> >> AT=: 2 :0 >> >> u@v"v >> >> ) >> >> >> >> +:AT*: d. 1 >> >> 0 4x&p."0 0 0 >> >> +:@*: d. 1 >> >> 0 4x&p. >> > >> > Th> >> --- For information about J forums see >> >> http://www.jsoftware.com/forums.htm >> > -------------------------------------------------------------------- >> > -- For information about J forums see >> > http://www.jsoftware.com/forums.htm >> > -------------------------------------------------------------------- >> > -- For information about J forums see >> > http://www.jsoftware.com/forums.htm >> > >> > -------------------------------------------------------------------- >> > -- For information about J forums see >> > http://www.jsoftware.com/forums.htm >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > > > > -- > Devon McCormick, CFA > ^me^ at acm. > org is my > preferred e-mail > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
