My Math Forum Sign changes in computing Quartic function

 Algebra Pre-Algebra and Basic Algebra Math Forum

 March 17th, 2018, 04:59 PM #1 Newbie   Joined: Oct 2013 Posts: 20 Thanks: 0 Sign changes in computing Quartic function Ferrari method uses simpler cubic equation. For complex coefficients: $\displaystyle (0.75, 1.25)x^4 + (1, 0)x^3 + (-1.25, 0)x^2 + (1.5, -0.25)x + (1.75, -1)$ p=(-0.358131487889273, 0.891003460207612), q=(0.203643395074293, -1.232139222471), r=(0.16504232468481, -1.24136744052394) cubic: $\displaystyle (1, 0)z^3 + (0.716262975778547, -1.78200692041522)z^2 + (-1.32579830222339, 4.32727697225848 )z + (-1.47669643119404, -0.501834028936385)$ give me: z0=(0.0735802447326096, 0.597239257630761) z1=(0.814183883954958, -0.378413964503688 ) z2=(0.216950841028975, 0.190838972431456) thus u0=(-0.957554480251324, 0.784814249702993), u1=(0.523652798193374, -1.1664921945659), u2=(-0.670813287658593, -0.0279863206956172), u3=(1.10471496971654, 0.409664265558529) and x0=(-1.04578977436897, 0.931873073232405), x1=(0.435417504075727, -1.01943337103649), x2=(-0.75904858177624, 0.119072502833795), x3=(1.0164796755989, 0.556723089087941) BUT for $\displaystyle (1.25, 1.25)x^4 + (1.75, -2)x^3 + (0.75, 0)x^2 + (1.5, 0.75)x + (0, -1.75)$ p=(1.14, -0.4125), q=(1.22425, 0.32625), r=(-0.6591203125, -0.306625) cubic $\displaystyle (1, 0)x^3 + (-2.28, 0.825)x^2 + (3.765925, 0.286)x + (1.392349, 0.798823125)$ z0=(0.285858156895703, 0.0619552424669605) z1=(0.316519149892536, -0.576284935944994) z2=(0.362094330796378, 0.739640982532143) I must change z0 to -z0 (or z1 to -z1 or z2 to -z2) and z0=(-0.285858156895703, -0.0619552424669605) u0=(-0.964471637584617, -0.22531128905411), u1=(0.24028297599186, -1.25397067601018), u2=(0.331433337799545, 1.3778811609441), u3=(0.392755323793212, 0.101400804120189) x0=(-0.939471637584617, 0.14968871094589), x1=(0.265282975991861, -0.878970676010176), x2=(0.356433337799545, 1.7528811609441), x3=(0.417755323793212, 0.476400804120189) In near 50% I must change. How determine, if I must change SIGN or not? Last edited by skipjack; March 17th, 2018 at 09:07 PM.

 Tags computing, function, polynomial, quartic, sign

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post taylor_1989_2012 Calculus 5 October 4th, 2016 03:17 AM fysmat Applied Math 7 March 1st, 2014 08:17 AM Niko Bellic Trigonometry 1 May 29th, 2012 08:29 PM meian2012 Linear Algebra 1 September 11th, 2010 03:33 PM dannyboycurtis Real Analysis 2 October 26th, 2009 09:54 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top