[racket] weirdness with complex numbers

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Tue Aug 7 18:28:11 EDT 2012

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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