Solve Quartic with Casio FX115MS

09022019, 02:35 PM
(This post was last modified: 09022019 02:37 PM by Albert Chan.)
Post: #6




RE: Solve Quartic with Casio FX115MS
(08302019 02:02 PM)Albert Chan Wrote: An old algorithm for solving Quartics: Brown's method ... To show AY/2 trick work, let roots, [c1,c2] = [p+q, pq], [d1,d2] = [r+s,rs] C = c1 d2 + c2 d1 = (p+q)(rs) + (pq)(r+s) = (pr  ps + qr  qs) + (pr + ps  qr  qs) = 2pr  2qs = 2(A/2)(Y/2)  2qs = AY/2  2qs If AY/2 = C, then 2qs = 0, sort order does not matter. If AY/2 > C, then 2qs > 0, thus c,d roots sorted the same way. If AY/2 < C, then 2qs < 0, thus c,d roots sorted opposite way. 

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Messages In This Thread 
Solve Quartic with Casio FX115MS  Albert Chan  11292018, 05:28 PM
RE: Solve Quartic with Casio FX115MS  Albert Chan  11292018, 10:31 PM
RE: Solve Quartic with Casio FX115MS  Albert Chan  02042019, 01:39 PM
RE: Solve Quartic with Casio FX115MS  Albert Chan  08242019, 12:47 PM
RE: Solve Quartic with Casio FX115MS  SlideRule  03142020, 01:28 AM
RE: Solve Quartic with Casio FX115MS  Albert Chan  08302019, 02:02 PM
RE: Solve Quartic with Casio FX115MS  Albert Chan  09022019 02:35 PM
RE: Solve Quartic with Casio FX115MS  Albert Chan  02012020, 12:27 PM
RE: Solve Quartic with Casio FX115MS  Albert Chan  03132020, 06:30 PM

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