# [racket] weirdness with complex numbers

Wolfram
http://www.wolframalpha.com/input/?i=roots+x%5E2+%2B+2*x+%2B+10
On Tue, Aug 7, 2012 at 6:28 PM, Matthias Felleisen <matthias at ccs.neu.edu>wrote:
>*
*>* If it weren't against math conventions, I wouldn't mind seeing 1-i1 or
*>* 1/2+i2/3. But I am sure the people who produce Racket or Scheme or Lisp
*>* readers would hate me for that one, too. I think your students will need to
*>* cope, like all people who study sophisticated concepts (such as complex).
*>*
*>* Anyone know how Mathematica copes?
*>*
*>*
*>* On Aug 6, 2012, at 6:05 PM, Todd O'Bryan wrote:
*>*
*>* > I just discovered that the way you enter (and display) a number like
*>* >
*>* > 1/2 + (2/3)i
*>* >
*>* > in Racket (and Scheme, presumably) is 1/2+2/3i.
*>* >
*>* > I understand why that is, and can't think of what else to do, but has
*>* > anyone had students get confused because the form looks like the i is
*>* > in the denominator of the imaginary part?
*>* >
*>* > What's more potentially confusing is that 1/2+2i/3 is a legal
*>* > identifier in its own right.
*>* >
*>* > I'm working on a program that models basic algebra in the way that
*>* > high school students are taught to do it, and one of my self-imposed
*>* > rules has been that "math should look like math." In other words, I'm
*>* > trying to minimize the conversion gymnastics that students have to put
*>* > up with when they enter math in calculators or computer programs. In
*>* > that spirit, I'm not sure if it would be better to allow the
*>* > inconsistency with the way order of operations normally works or just
*>* > have students enter 1/2+(2/3)i (or 1/2+2i/3, maybe) and do the
*>* > conversion behind the scenes.
*>* >
*>* > Anyone have any thoughts or prejudices one way or the other?
*>* >
*>* > Todd
*>* > ____________________
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*>* > http://lists.racket-lang.org/users
*>*
*>*
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