(12C Platinum) Cubic Equation
02-05-2019, 10:24 PM
Post: #8
 Albert Chan Senior Member Posts: 2,354 Joined: Jul 2018
RE: (12C Platinum) Cubic Equation
(02-04-2019 08:13 PM)Thomas Klemm Wrote:  $$x^3 - 4x^2 + 6x - 24 = 0$$

Enter coefficients:

1 CF0
-4 CFj
6 CFj
-24 CFj

Enter guess:

20 R/S
4.0000

Above entered coefficients order are good for root finding, and to evaluate polynomial.

Example, with above entered polynomial, calculate f(X = 12.34)

1 Enter 12.34 [Δ%] [i] ; showed rate of 1134%, X = 1 + i

NPV 0 PMT FV CHS ; showed 1320.018504 <-- f(X)

Confirm with Horners rule:

12.34 Enter Enter Enter RCL 0
* RCL 1 +
* RCL 2 +
* RCL 3 + ; showed 1320.018504

Doing the same with reversed ordered entry is not as accurate:

24 CHS CF0
6 CFj
4 CHS CFj
1 CFj

1 Enter 12.34 [1/x] [Δ%] [i] ; showed rate of -91.89627229%, X = 1/(1 + i)

NPV ; showed 1320.018507, +3 ULP error
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 Messages In This Thread (12C Platinum) Cubic Equation - Gamo - 01-12-2019, 09:27 AM RE: (12C Platinum) Cubic Equation - Albert Chan - 01-12-2019, 01:39 PM RE: (12C Platinum) Cubic Equation - Albert Chan - 02-04-2019, 04:10 PM RE: (12C Platinum) Cubic Equation - Thomas Klemm - 02-04-2019, 08:13 PM RE: (12C Platinum) Cubic Equation - Albert Chan - 02-05-2019 10:24 PM RE: (12C Platinum) Cubic Equation - Gamo - 02-05-2019, 04:24 AM RE: (12C Platinum) Cubic Equation - Thomas Klemm - 02-05-2019, 06:09 AM RE: (12C Platinum) Cubic Equation - Thomas Klemm - 02-05-2019, 06:20 AM

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