(SQRT 0 1i ) ^2

General discussion about calculators, SwissMicros or otherwise
J-F Garnier
Posts: 47
Joined: Sun Mar 11, 2018 5:37 pm
Location: France

Re: (SQRT 0 1i ) ^2

Post by J-F Garnier »

Over_score wrote:
Thu Jun 23, 2022 8:33 pm
I tend to say the WP43S result is the better one because it's the correctly rounded result.
0.4822862220714997783980731069786049561748... + i×0.4822862220714997783980731069786049561748... is the correct result according to WolframAlpha.
So the correctly rounded result to 34 digits is:
0.4822862220714997783980731069786050 + i×0.4822862220714997783980731069786050
OK, good point. And so the "error" in the squared back value is just a consequence of the finite number(s) - same discussion.
And again, the "error" more likely appears when the square root number (to be rounded) is not far from between rounding up/down, here: 0.4822862220714997783980731069786049(562), i.e. the loss of information is maximum.

J-F
Panchdara
Posts: 148
Joined: Sat May 15, 2021 9:02 am

Re: (SQRT 0 1i ) ^2

Post by Panchdara »

If you don't understand it, then it must be intuitively obvious.... never assume a float/real is perfect in a 2-dimensional world. :oops:
redglyph
Posts: 177
Joined: Sat Dec 22, 2018 11:45 am

Re: (SQRT 0 1i ) ^2

Post by redglyph »

I doubt there are practical cases where that makes any difference. Selecting the required precision with ENG, SCI or FIX rounds the displayed result, making those little epsilons disappear. They're well beyond any measurement's uncertainty anyway.
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