arianbig

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7 years, 125 days

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These are questions asked by arianbig

Hi
sry guys i have a problem with my maple when i use my fsolve sometimes it gave me no solution but i khow we have a solution ill use simplify to gave it a simplified input but also no awenser is there any other command yo make my problem easier for maple and also is there anyway that i can force my cpu and memory to focus more on solving problems

and at last what is default method for fsolve ( i mean is it newton method or something else and can i change it )

tnQ for your attentions
thats my maple file problem.mw

 

i have 4 equation and 4 variables with DirectSearch package it will give me a solution but not in a good time
when i try fsolve it just give me a blank
these are my equations :
POL[0] := .42810/(.65429+c[-2])

 POL[1] := -8.4078*c[-1]-162.64*c[0]+84.228*c[1]-6/(.80888+c[-2])^2+9.7066/(.80888+c[-2])^3-3.9257/(.80888+c[-2])^4+(1/2*(.42786*c[-1]+.42786*c[0]+.42786*c[1]+.65429/(.80888+c[-2])))*(-49.180*c[-1]+31.921*c[0]-8.6921*c[1]+2/(.80888+c[-2])-3.2355/(.80888+c[-2])^2+1.3086/(.80888+c[-2])^3)

POL[2] := 53.965*c[-1]+43.012*c[0]-103.98*c[1]-6/(1.+c[-2])^2+12./(1.+c[-2])^3-6./(1.+c[-2])^4+(1/2*(.50000*c[-1]+.50000*c[0]+.50000*c[1]+1./(1.+c[-2])))*(22.229*c[-1]-37.815*c[0]+22.229*c[1]+2/(1.+c[-2])-4./(1.+c[-2])^2+2./(1.+c[-2])^3)

POL[3] := -30.115*c[-1]+43.264*c[0]+52.171*c[1]-6/(1.2363+c[-2])^2+14.836/(1.2363+c[-2])^3-9.1704/(1.2363+c[-2])^4+(1/2*(.52893*c[-1]+.52893*c[0]+.52893*c[1]+1.5284/(1.2363+c[-2])))*(-4.5997*c[-1]+16.892*c[0]-26.026*c[1]+2/(1.2363+c[-2])-4.9452/(1.2363+c[-2])^2+3.0568/(1.2363+c[-2])^3)

i even change digits to 100 but still no awenser

my fsolve syntax

K := fsolve({seq(POL[v], v = 0 .. 2*N+2)})

the awenser fsolve gave me

K:=

thats all it gave me

hey everyone
i got a little problem here i really dont get it why my fsolve give me this error

Error, (in sqrfree) argument must be a polynomial or a rational function in {cf[-2], cf[-1], cf[0], cf[1]}
these are my variables :


cf[-2], cf[-1], cf[0], cf[1]}


thats part of my code :

res1;
(34.30563197 cf[-1] - 10.13498047 cf[0] + 5.197134649 cf[1]

   - 0.4714805434) (0.3095515346 cf[-2] + 0.3822521253) - (cf[-1](2.466022067

  ) + cf[0](-0.6605923783) + cf[1](1.076415647))^2

   - cf[-1](2.466022067) - cf[0](-0.6605923783)

   - cf[1](1.076415647) - 333.1166471 cf[-1] + 186.8672744 cf[0]

   - 128.6145289 cf[1] + 0.8737683108, (-39.73727883 cf[-1]

   + 26.25682759 cf[0] - 7.289811219 cf[1] - 0.3506934780)

  (0.4161980514 cf[-1] + 0.4402863507) - (cf[-1](0.3227083347)

   + cf[0](2.517826949) + cf[1](-0.7889944208))^2

   - cf[-1](0.3227083347) - cf[0](2.517826949)

   - cf[1](-0.7889944208) - 15.03436409 cf[-1]

   - 129.5665191 cf[0] + 68.25827819 cf[1] + 0.5888637790,

  (17.36111111 cf[-1] - 29.80788311 cf[0] + 17.36111111 cf[1]

   - 0.2500000000) (0.5000000000 cf[0] + 0.5000000000)

                                                            2
   - (cf[-1](-1.833333334) + cf[0](0.) + cf[1](2.333333334))

   - cf[-1](-1.833333334) - cf[0](0.) - cf[1](2.333333334)

   + 38.17276297 cf[-1] + 34.00261850 cf[0] - 77.23526300 cf[1]

   + 0.3750000000, (-3.548332053 cf[-1] + 12.78057007 cf[0]

   - 19.34221012 cf[1] - 0.1707008416) (0.5290914191 cf[1]

   + 0.5597136492) - (cf[-1](1.060931345) + cf[0](-1.540306477)

   + cf[1](-0.2297630675))^2 - cf[-1](1.060931345)

   - cf[0](-1.540306477) - cf[1](-0.2297630675)

   - 20.59209188 cf[-1] + 28.27859544 cf[0] + 40.45630289 cf[1]

         -10                      
   + 1 10    cf[-2] + 0.2254717519


fsolve({seq(res1[v] = 0, v = 1 .. 2*N+2)})     ( N here is 1 )

why i cant get the awenser and if you can plz solve it for me

i would be happy that anyone can give me an explanation with details

tnX a lot

Arian
 

 

when i want to get awenser i have to solve it for 36 equation and 36 variabales
but maple will not give me a solution (just toss me back my variabales ) i dont know whats wrong
it will give me an awenser for lower like 20equ and 20var ?
parameters :

there is m for power an equation (equation^m) its between 2 , 2.5 , 3 , 4
and N give 2N+2var and 2N+2equ
its a hard calculation i copy it here hope u get it

h= "a number "

p := proc (x) c[-N-1]*x^2+1 end proc

dp := diff(p(x), x)

ddp := diff(p(x), x, x)

DELTA2 := piecewise(k <> j, -2*(-1)^(j-k)/(j-k)^2, k = j, -(1/3)*Pi^2)/h^2

DELTA1 := piecewise(k <> j, (-1)^(j-k)/(j-k), k = j, 0)/h

DELTA0 := piecewise(k <> j, 0, k = j, 1)

PHI := proc (x) ln(sinh(x)) end proc

dPHI := diff(PHI(x), x)

ddPHI := diff(PHI(x), x, x)
 

for i from -N-1 to N do x[i] := ln(exp(i*h)+(exp(2*i*h)+1)^(1/2)) end do

variabales : c[-N-1],c[-N],c[-N+1]...c[N-1],c[N] total 2N+2 var



My equations

POL := seq(simplify(eval(sum(c[k]*((eval(2*dPHI*DELTA1), x = x[j])+eval(x[j]*ddPHI*DELTA1, x = x[j])+x[j]*(eval(dPHI^2, x = x[j]))*DELTA2), k = -N .. N)+eval(ddp, x = x[j])+2*(sum(c[k]*(eval(x[j]*dPHI*DELTA1, x = x[j])+DELTA0), k = -N .. N)+eval(dp, x = x[j]))/x[j]+(c[j]*x[j]+p(x[j]))^m, x = x[j])), j = -N-1 .. N)

solving

K := fsolve({seq(POL[v] = 0, v = 1 .. 2*N+2)})

it can calculate for m=2.5 , N=15 , h=0.29669

if you can calculate it for m=3 , N=17 , h=0.41600

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