Yes, good point. Surely it's less trouble if we pretend it makes sense to refer to i and -i separately. But of course, given that U and V are each a root of X^2 + 1 , we could equally tell whether they are the same or different according as UV = -1 or UV = +1 , without referring to either of them separately. --Dan
On Mar 2, 2015, at 10:19 AM, Eugene Salamin via math-fun <math-fun@mailman.xmission.com> wrote:
When a square root of -1 appears more than once in an exposition, it is necessary to have a way of indicating whether two such occurrences are the same or different square roots. The use of i and -i satisfies that requirement. -- Gene
From: Dan Asimov <dasimov@earthlink.net> To: math-fun <math-fun@mailman.xmission.com> Sent: Sunday, March 1, 2015 7:13 PM Subject: Re: [math-fun] ln
What bothers me is the unqualified use of sqrt(-1) to mean i, since I think that should always be described as a convention.
Sometimes it seems to me we have no right to use a symbol for i, just because there is no way to distinguish between i and -i. Maybe we should be allowed only to refer to both of them at once.
--Dan
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