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[BUG?] Wrong numeric result with CAS `fsolve`/`zeros`/`solve`
12-19-2016, 04:15 AM
Post: #1
[BUG?] Wrong numeric result with CAS `fsolve`/`zeros`/`solve`
I was reading this post in another forum http://forum.hp-prime.de/showthread.php?tid=183

and can confirm that all of the following result in the wrong root 0 on the Prime:
zeros(x^4 - 3x^3 - 2.75x^2 + 12x - 5)
solve(x^4 - 3x^3 - 2.75x^2 + 12x - 5 = 0)
fsolve(x^4 - 3x^3 - 2.75x^2 + 12x - 5 = 0)
-> [2.5, 2., -2., 0]

The correct result would be:
-> [2.5, 2., -2., 0.5]

Firmware version: 2016 08 29 (10637)

The same commands work correctly with giac 1.2.2.

Also, the exact version works on the Prime:
zeros(x^4 - 3x^3 - (275/100)*x^2 + 12x - 5)
-> [2, -2, 5/2, 1/2]


This looks more significant than a small rounding error.
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[BUG?] Wrong numeric result with CAS `fsolve`/`zeros`/`solve` - danielmewes - 12-19-2016 04:15 AM



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