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+--- Thread: Mistake Copying from History Screen (/thread-9324.html)
Mistake Copying from History Screen - Helge Gabert - 10-18-2017 09:06 PM
On the physical prime, I recently ran into a problem copying an intermediate expression, such as 1/(1+i)*x^(1+i), which resulted from integrating x^i dx in the CAS environment.
Highlighting this expression, and copying into the command line, results in 1/(1+i)*x^1+i. If one is not super careful, this is easy to miss and later calculations will be off.
RE: Mistake Copying from History Screen - webmasterpdx - 10-18-2017 09:33 PM
x^(1+i) copies and pastes to the command line as x^1+i too.
RE: Mistake Copying from History Screen - Helge Gabert - 10-18-2017 09:44 PM
Yup, it sure does. Also x^(1-i), which becomes x-i.
RE: Mistake Copying from History Screen - webmasterpdx - 10-19-2017 04:39 AM
In Cas, you can do x^(a+b*i) and it'll copy correctly, but with numeric's, it get's it wrong. Note that I also used Copy to do it with the same result...the problem is in the copy not the paste (if that helps).
RE: Mistake Copying from History Screen - Tim Wessman - 10-19-2017 04:45 AM
Its actually not anything in the copy code. Rather, its in the printing of the result. Turn off the 2D stuff and you'll see it still happens.
The 2D code is smart enough to recognize 1+i as a complex and keep it grouped which is why the answer looks correct, but by that time the cas has evaluated and the parens have already been stripped. So when you copy it back x^1+i is actually correctly being interpreted.
RE: Mistake Copying from History Screen - webmasterpdx - 10-19-2017 06:30 AM
What? x^(1+i) is not equal to x^1 + i
....which makes this a bug. I usually don't look closely at what's pasted, so I can see people making mistakes due to not seeing the error.
RE: Mistake Copying from History Screen - Arno K - 10-19-2017 08:22 AM
So just another issue with copying result from history to the input line, Algebraic modes seems to recognize the complex, also no bracket is displayed in history when the complex is the last item there, on copying to textbook input line these missing brackets are not seen and so the final result simply is wrong. If I remember correctly some time ago there was something similar.
Arno
Edit: When textbook display is switched of x^(1+i) is transformed to x^1 +i on parsing the entry. Things seem to become worse.
RE: Mistake Copying from History Screen - Helge Gabert - 10-20-2017 05:34 PM
So, to recap, after entering int(x^i,x):
The <Show> soft key displays the result correctly.
The <Copy> soft key displays (and enters) the result incorrectly.
Also, after entering just x^(1+i):
a) Highlighting x^(1+i) on the left hand side of the history screen copies correctly into the command line.
b) Highlighting x^(1+i) on the right side of the history screen copies as x^1+i, or x+i. But again,<Show> displays x^(1+i).
I can't believe this behavior has always existed - - it must have been correct in previous firmware versions (or else, I produced a bunch of wrong results, and nobody noticed (!)).
RE: Mistake Copying from History Screen - Tim Wessman - 10-20-2017 05:39 PM
(10-19-2017 06:30 AM)webmasterpdx Wrote: What? x^(1+i) is not equal to x^1 + i
....which makes this a bug. I usually don't look closely at what's pasted, so I can see people making mistakes due to not seeing the error.
What I was saying was that yes, it was a problem with the printing coming out of the CAS. However, the 2D part (copying the result) was actually working properly with what it was (incorrectly) getting from the CAS. Thats all.
RE: Mistake Copying from History Screen - webmasterpdx - 10-21-2017 01:19 AM
Has anyone found and fixed this bug in the firmware for future release yet?
RE: Mistake Copying from History Screen - DrD - 10-21-2017 10:39 AM
Future release? (... like a dog with its nose up in air, I say ... "sniff, sniff")?
RE: Mistake Copying from History Screen - webmasterpdx - 10-21-2017 11:05 AM
Keep dreamin' LOL!