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sqrt question
04-06-2017, 06:18 PM (This post was last modified: 04-06-2017 06:21 PM by Han.)
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RE: sqrt question
(04-06-2017 06:03 PM)KeithB Wrote:  So to summarize, by assuming sqrt(-4) is a valid operation we are automatically going to interpret it as 2i.

No, the point was that in choosing to evaluate \( \sqrt{-4} \cdot \sqrt{-9} \) to be equal to -6 (by following the order of operations), we have implicitly made the assumption that \( \sqrt{ x } = i \sqrt{|x|} \) for \( x < 0 \).

The conventional use of \( \sqrt{x} \) is that it is the positive square root of \( x \). There is no single convention, however, for \( \sqrt{x} \) if \( x < 0 \).

EDIT: One could also argue that we may have actually implicitly assumed that \( \sqrt{x} = -i \sqrt{|x|} \) for \( x < 0 \). We still get -6, but all the more reason that there is no single convention for \( \sqrt{x} \) for negative values of \( x \).

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Messages In This Thread
sqrt question - KeithB - 04-06-2017, 03:25 PM
RE: sqrt question - pier4r - 04-06-2017, 04:01 PM
RE: sqrt question - Namir - 04-06-2017, 04:02 PM
RE: sqrt question - KeithB - 04-06-2017, 04:51 PM
RE: sqrt question - Han - 04-06-2017, 05:46 PM
RE: sqrt question - pier4r - 04-06-2017, 05:15 PM
RE: sqrt question - KeithB - 04-06-2017, 06:03 PM
RE: sqrt question - Han - 04-06-2017 06:18 PM
RE: sqrt question - Claudio L. - 04-07-2017, 01:23 PM
RE: sqrt question - Han - 04-07-2017, 04:48 PM
RE: sqrt question - Claudio L. - 04-07-2017, 09:15 PM
RE: sqrt question - Han - 04-07-2017, 10:54 PM
RE: sqrt question - Claudio L. - 04-09-2017, 03:59 AM
RE: sqrt question - David Hayden - 04-24-2017, 09:36 PM
RE: sqrt question - Claudio L. - 04-26-2017, 03:08 AM
RE: sqrt question - Han - 04-28-2017, 06:09 PM
RE: sqrt question - nsg - 04-07-2017, 11:34 PM
RE: sqrt question - Vtile - 04-09-2017, 10:41 AM
RE: sqrt question - nsg - 04-09-2017, 05:26 PM
RE: sqrt question - Vtile - 04-09-2017, 11:07 PM
RE: sqrt question - nsg - 04-10-2017, 01:44 AM
RE: sqrt question - Vtile - 04-25-2017, 11:38 PM



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