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Error, (in evala/preproc3) floats not handled yet...

Asked by: farahnaz 15
eigenvectors
June 23 2016
0  3

hi.i have a problem with gain Eigenvectors

please help me

thanks

lorenz_1.mw

> 

restart; with(LinearAlgebra[Modular]); A := Matrix(3, 3, [[-a, a, 0], [0, 0, -sqrt(l.b.c.(h+k))/(h+k)], [(2.*h.sqrt(l.b.c.(h+k)))/(l.(h+k)), (2.*k.sqrt(l.b.c.(h+k)))/(l.(h+k)), -c]])

A := Matrix(3, 3, {(1, 1) = -a, (1, 2) = a, (1, 3) = 0, (2, 1) = 0, (2, 2) = 0, (2, 3) = -(`.`(l, b, c, h+k))^(1/2)/(h+k), (3, 1) = 2.*(h.((`.`(l, b, c, h+k))^(1/2)))/(l.(h+k)), (3, 2) = 2.*(k.((`.`(l, b, c, h+k))^(1/2)))/(l.(h+k)), (3, 3) = -c})

 (1)
> 

Sol := LinearAlgebra[Eigenvectors](A)

Error, (in evala/preproc3) floats not handled yet

  
> 

``


Download lorenz_1.mw

What is the advantage and disadvantage of RK45 re...

Asked by: faisal 15
June 22 2016
0  0

DEAR SIR,

PLEASE HELP ME WITH THAT QUESTION

Suddenly I can't open my Maple file...

Asked by: Traruh Synred 55
June 20 2016
1  24

MAPLE 15 on Windows 10

I have a file on which I can no longer open. This happened after my computer made me long on again after being gone for a little while. Maple was not running when I got back on. This is not unusal and I just clinck on the file and restart.

This time this did not work.

It comes up with a message asking me to select an input mode. Whatever I select even 'Plain text' it just hangs.

I'd send you an image, but I don't see how to do it. The button provide only allows for something with  url and the snip I made is on my desktop.

I need to get thiis worksheet back. I've put a lot of effort into it.

-Traruh

Errors in code ...

Asked by: iman 35
dsolve stringtools
June 19 2016
0  11

hi.please help me for solve this equation

i encounter with error''

Error, (in StringTools:-IsPrefix) second argument must be a string''

equations which be solved attached as pdf file

thanks

Kernel4.mw

root.pdf
 
> 

restart
> 

with(LinearAlgebra):
> 

Typesetting:-Settings(functionassign=false):
> 

NULL

Constants
 
> 

landa := 0.404e11; -1; mu := 0.27e11; -1; alpha := 0.23e-4; -1; rho := 2707; -1; k := 204; -1; c := 903; -1; nu := .3; -1; E := 0.70e11; -1; T0 := 293; -1; omega := 0.1e-1

0.1e-1

 (1.1.1)
> 

beta := alpha*(3*landa+2*mu):
> 

NULL
> 

varpi := 0.1e-1; -1; No := 15

15

 (1.1.2)

 

 
> 

Eq[1] := besselj(0, xi*b)*(eval(diff(bessely(0, xi*r), r), r = a))-(eval(diff(besselj(0, xi*r), r), r = a))*bessely(0, xi*b):
> 

 

> 

wf1 := unapply(Eq[1], xi):

1

  

1.794010904

  

1

  

2

  

1.794010904

  

1

  

3

  

4.802060761

  

2

  

4

  

4.802060761

  

2

  

5

  

4.802060761

  

2

  

6

  

7.908961712

  

3

  

7

  

7.908961712

  

3

  

8

  

7.908961712

  

3

  

9

  

11.03509457

  

4

  

10

  

11.03509457

  

4

  

11

  

11.03509457

  

4

  

12

  

11.03509457

  

4

  

13

  

14.16798650

  

5

  

14

  

14.16798650

  

5

  

15

  

14.16798650

  

5

  

16

  

17.30400975

  

6

 (1.2.1)
> 

Eq[2] := MTM:-besselj(1, eta*b)*(eval(diff(MTM:-bessely(1, eta*r), r), r = a))-(eval(diff(MTM:-besselj(1, eta*r), r), r = a))*MTM:-bessely(1, eta*b):
> 

wf2 := unapply(Eq[2], eta):

1

  

1.958510605

  

1

  

2

  

1.958510605

  

1

  

3

  

4.857021628

  

2

  

4

  

4.857021628

  

2

  

5

  

4.857021628

  

2

  

6

  

7.941288451

  

3

  

7

  

7.941288451

  

3

  

8

  

7.941288451

  

3

  

9

  

11.05802155

  

4

  

10

  

11.05802155

  

4

  

11

  

11.05802155

  

4

  

12

  

11.05802155

  

4

  

13

  

14.18576207

  

5

  

14

  

14.18576207

  

5

  

15

  

14.18576207

  

5

  

16

  

17.31852918

  

6

 (1.2.2)
> 

 

> 

for m to MM do K0[m] := proc (r, m) options operator, arrow; BesselJ(0, xi[m]*r)*BesselY(0, xi[m]*b)-BesselJ(0, xi[m]*b)*BesselY(0, xi[m]*r) end proc; KK0[m] := proc (r, m) options operator, arrow; diff(K0[m](r, m), r) end proc; K1[n] := proc (r, n) options operator, arrow; BesselJ(1, eta__n*r)*BesselY(1, eta__n*b)-BesselJ(1, eta__n*b)*BesselY(1, eta__n*r) end proc; KK1[n] := proc (r, n) options operator, arrow; diff(K1[n](r, n), r) end proc end do

proc (r, m) options operator, arrow; BesselJ(0, xi[m]*r)*BesselY(0, xi[m]*b)-BesselJ(0, xi[m]*b)*BesselY(0, xi[m]*r) end proc

  

proc (r, m) options operator, arrow; MTM:-diff(K0[m](r, m), r) end proc

  

proc (r, n) options operator, arrow; BesselJ(1, eta__n*r)*BesselY(1, eta__n*b)-BesselJ(1, eta__n*b)*BesselY(1, eta__n*r) end proc

  

proc (r, n) options operator, arrow; MTM:-diff(K1[n](r, n), r) end proc

  

proc (r, m) options operator, arrow; BesselJ(0, xi[m]*r)*BesselY(0, xi[m]*b)-BesselJ(0, xi[m]*b)*BesselY(0, xi[m]*r) end proc

  

proc (r, m) options operator, arrow; MTM:-diff(K0[m](r, m), r) end proc

  

proc (r, n) options operator, arrow; BesselJ(1, eta__n*r)*BesselY(1, eta__n*b)-BesselJ(1, eta__n*b)*BesselY(1, eta__n*r) end proc

  

proc (r, n) options operator, arrow; MTM:-diff(K1[n](r, n), r) end proc

  

proc (r, m) options operator, arrow; BesselJ(0, xi[m]*r)*BesselY(0, xi[m]*b)-BesselJ(0, xi[m]*b)*BesselY(0, xi[m]*r) end proc

  

proc (r, m) options operator, arrow; MTM:-diff(K0[m](r, m), r) end proc

  

proc (r, n) options operator, arrow; BesselJ(1, eta__n*r)*BesselY(1, eta__n*b)-BesselJ(1, eta__n*b)*BesselY(1, eta__n*r) end proc

  

proc (r, n) options operator, arrow; MTM:-diff(K1[n](r, n), r) end proc

  

proc (r, m) options operator, arrow; BesselJ(0, xi[m]*r)*BesselY(0, xi[m]*b)-BesselJ(0, xi[m]*b)*BesselY(0, xi[m]*r) end proc

  

proc (r, m) options operator, arrow; MTM:-diff(K0[m](r, m), r) end proc

  

proc (r, n) options operator, arrow; BesselJ(1, eta__n*r)*BesselY(1, eta__n*b)-BesselJ(1, eta__n*b)*BesselY(1, eta__n*r) end proc

  

proc (r, n) options operator, arrow; MTM:-diff(K1[n](r, n), r) end proc

  

proc (r, m) options operator, arrow; BesselJ(0, xi[m]*r)*BesselY(0, xi[m]*b)-BesselJ(0, xi[m]*b)*BesselY(0, xi[m]*r) end proc

  

proc (r, m) options operator, arrow; MTM:-diff(K0[m](r, m), r) end proc

  

proc (r, n) options operator, arrow; BesselJ(1, eta__n*r)*BesselY(1, eta__n*b)-BesselJ(1, eta__n*b)*BesselY(1, eta__n*r) end proc

  

proc (r, n) options operator, arrow; MTM:-diff(K1[n](r, n), r) end proc

  

proc (r, m) options operator, arrow; BesselJ(0, xi[m]*r)*BesselY(0, xi[m]*b)-BesselJ(0, xi[m]*b)*BesselY(0, xi[m]*r) end proc

  

proc (r, m) options operator, arrow; MTM:-diff(K0[m](r, m), r) end proc

  

proc (r, n) options operator, arrow; BesselJ(1, eta__n*r)*BesselY(1, eta__n*b)-BesselJ(1, eta__n*b)*BesselY(1, eta__n*r) end proc

  

proc (r, n) options operator, arrow; MTM:-diff(K1[n](r, n), r) end proc

 (1.2.3)
> 

> 

U1 := -(int(r*K0[m]*(diff(K1[n], r)+K1[n]/r), r = a .. b))/(int(r*K0[m]^2, r = a .. b)); -1; U2 := -(int(r*K1[n]*(diff(K0[m], r)), r = a .. b))/(int(r*K1[n]^2, r = a .. b)); -1; U3 := (int(r^2*omega^2*K1[n], r = a .. b))/(int(r*K1[n]^2, r = a .. b))

0.1555555555e-3/K1[0]

 (1.2.4)
> 

m := 0; -1; for m to MM do M__m := int(r*K1[m](r, m)^2, r = a .. b); bb__m := 1/M__m end do

int(r*K1[1](r, 1)^2, r = 1 .. 2)

  

1/(int(r*K1[1](r, 1)^2, r = 1 .. 2))

  

int(r*K1[2](r, 2)^2, r = 1 .. 2)

  

1/(int(r*K1[2](r, 2)^2, r = 1 .. 2))

  

int(r*K1[3](r, 3)^2, r = 1 .. 2)

  

1/(int(r*K1[3](r, 3)^2, r = 1 .. 2))

  

int(r*K1[4](r, 4)^2, r = 1 .. 2)

  

1/(int(r*K1[4](r, 4)^2, r = 1 .. 2))

  

int(r*K1[5](r, 5)^2, r = 1 .. 2)

  

1/(int(r*K1[5](r, 5)^2, r = 1 .. 2))

  

int(r*K1[6](r, 6)^2, r = 1 .. 2)

  

1/(int(r*K1[6](r, 6)^2, r = 1 .. 2))

 (1.2.5)
> 

MM; 1; n; 1; m; 1; U1; 1; U2; 1; U3; 1; xi

6

  

0

  

7

  

-(2/3)*K1[0]/K0[7]

  

0

  

0.1555555555e-3/K1[0]

  

xi

 (1.2.6)
> 

for m to MM do for n to MM do dsys := {diff(S[m][n](t), t, t, t)+xi^2*[m]*(diff(S[m][n](t), t, t))+(-U1*U2+`η__η__n__`^2)*(diff(S[m][n](t), t))+xi[m]^2*`η__η__n__`^2*S[m][n](t) = -(2*U2*bb[m]/(Pi*xi[m])*(-BesselJ(0, xi[m]*b)/BesselJ(1, xi[m]*a)))*q+xi^2*[m]*U3} end do end do; sol := dsolve(dsys)

Error, (in StringTools:-IsPrefix) second argument must be a string

  
> 

 

> 

NULL
> 

for m to MM do for n to MM do dsys2 := {diff(Q__mn(t), t, t, t)+xi[m]^2*(diff(Q__mn(t), t, t))+(-U1*U2+eta__n^2)*(diff(Q__mn(t), t))+xi[m]^2*eta__n^2*Q__mn(t) = -2*BesselJ(0, xi[m]*b)*U1*U2*b__m*(1-exp(-xi[m]^2*t))/(BesselJ(1, xi[m]*a)*Pi*xi[m]^3)} end do end do;
> 

sol2 := dsolve(dsys2)

Error, (in dsolve) invalid input: `PDEtools/sdsolve` expects its 1st argument, SYS, to be of type Or(set({`<>`, `=`, algebraic}), list({`<>`, `=`, algebraic}), `casesplit/ans`(list, list)), but received [{Q__mn(t)*pochhammer(1-n, n)+(1497143767/5000000)*(diff(Q__mn(t), [`$`(t, t)]))+eta__n^2*(diff(Q__mn(t), t))+(1497143767/5000000)*eta__n^2*Q__mn(t) = 0}]

  
> 

``

NULL

NULL

 

Download Kernel4.mw

How to refer to previous result?...

Asked by: MrYouMath 40
June 08 2016
0  9

I want to reference the previous equation/expression which is not displayed (':')in my worksheet. I allready know the '%' sign, but this references the previous equation/expression which was executed . By previous I mean the result (which is not displayed) in the previous line.

As I do not want the previous equation to be displayed I also cannot use the equation lable (CTRL+L).

 

Example

x:=a=b+1:

solve(previous,{b});

 

Thank you for your help.

Maple doesn't recognize 'complexplot3d'...

Asked by: azzay42 10
June 08 2016
1  2

I'm new here, so I'm not totally sure this is the right place to ask this. I apologize if it isn't, please let me know in that case.

 

My problem is that Maple won't recognize the built-in command 'complexplot3d'. For example, typing:

complexplot3d(z^2, z = -1-I .. 1+I)

doesn't do anything, and it's displayed again in blue as if it was not a command.

 

Any kind of help would be extremely helpful, as I have no clue of what's going on. Thanks in advance!

How to solve polynomial system?...

Asked by: farahnaz 15
polynomial solve
May 27 2016
0  1

how i can solve equations and gain{p1,p2,q1,q2}?

thanks

solve.mw

Q1 := -mu1*p1-upsilon1*q1+gamma11*q1*(p1^2+q1^2)+gamma12*q1*(p2^2+q2^2)-delta1*(2*p1*q1*p2-q2*(p1^2-q1^2))-s11*F*q1+s12*F*q2 = 0

-mu1*p1-upsilon1*q1+gamma11*q1*(p1^2+q1^2)+gamma12*q1*(p2^2+q2^2)-delta1*(2*p1*q1*p2-q2*(p1^2-q1^2))-s11*F*q1+s12*F*q2 = 0

 (1)

Q2 := -mu1*q1+upsilon1*p1-gamma11*p1*(p1^2+q1^2)-gamma12*p1*(p2^2+q2^2)-delta1*(2*p1*q1*q2+p2*(p1^2-q1^2))-s11*F*p1-s12*F*p2 = 0

-mu1*q1+upsilon1*p1-gamma11*p1*(p1^2+q1^2)-gamma12*p1*(p2^2+q2^2)-delta1*(2*p1*q1*q2+p2*(p1^2-q1^2))-s11*F*p1-s12*F*p2 = 0

 (2)

Q3 := -mu2*p2-upsilon2*q2+gamma21*q2*(p1^2+q1^2)+gamma22*q2*(p2^2+q2^2)+delta2*(3*p1^2*q1-q1^3)+s21*F*q1 = 0

-mu2*p2-upsilon2*q2+gamma21*q2*(p1^2+q1^2)+gamma22*q2*(p2^2+q2^2)+delta2*(3*p1^2*q1-q1^3)+s21*F*q1 = 0

 (3)

Q4 := -mu2*q2+upsilon2*p2-gamma21*p2*(p1^2+q1^2)-gamma22*p2*(p2^2+q2^2)+delta2*(-p1^3+3*p1*q1^2)-s21*F*p1 = 0

-mu2*q2+upsilon2*p2-gamma21*p2*(p1^2+q1^2)-gamma22*p2*(p2^2+q2^2)+delta2*(-p1^3+3*p1*q1^2)-s21*F*p1 = 0

 (4)

SOLL := solve({Q1, Q2, Q3, Q4}, real)

Error, (in PolynomialSystemSolvers:-PseudoResultant) numeric exception: division by zero

  

SOLL := solve({Q1, Q2, Q3, Q4}, {p1, p2, q1, q2})

Warning,  computation interrupted

  

``

 

Download solve.mw

 

Replica of MATLAB code in Maple?...

Asked by: iman 35
May 22 2016
0  0

hi

if possible to convert matlab file in to maple fie program??convert_to_maple_program.txt

thanks

 

Incorrect syntax...

Asked by: iman 35
syntax programming
May 20 2016
0  1

hi.please help me for remove error'' 

Error, illegal use of an object as a name''

 

thanks

PLATE.mw

   

Parse:-ConvertTo1D, "first argument to _Inert_ASSIGN must be assignable"

Error, illegal use of an object as a name

"restart:Digits :=15: beta:=10:alpha:=100: xi:=.5: upsilon:=0.2841945289:n:=3: aa:=1:b:=1:N_x:=0.4:N_y:=0.4:N_xy:=0: hl2:=1:mu:=65.8e9:E:=169e9: delta0:=1:delta1:=1: mus:=3:D1:=2;h:=1: lambda:=0.1: D2:=5:A1:=-2:A2:=-2:A3:=-6:A4:=7:A5:=7:A6:=7:A7:=7:A8:=8:A9:=7:A10:=7:A11:=1: A12:=1:tau:=4.730040745:t:=0: g2:=sin(theta):g3:=cos(theta):g1:=cos(theta):a:=0.0:with(Student[Calculus1]): a1:=evalf((A1*ApproximateInt(g3^2,theta=a..1,method=simpson) ) ) : a2:= evalf(A2*ApproximateInt(g3*((&DifferentialD;)^2)/((&DifferentialD;theta)^2)g3,theta=a..1,method=simpson)): a3:=evalf(A3*ApproximateInt(g3*g3,theta=a..1,method=simpson)) : a4:=evalf(A4*ApproximateInt(g3*g3,theta=a..1,method=simpson)) :a5:=evalf(A5*ApproximateInt(g3^2,theta=a..1,method=simpson)) : a6:=evalf(A6*ApproximateInt(((&DifferentialD;)^2)/((&DifferentialD;theta)^2)g3*g3,theta=a..1,method=simpson)) :a7:=evalf(A7*ApproximateInt(g3*g3,theta=a..1,method=simpson)): a8:=evalf(A8*ApproximateInt(g3^2,theta=a..1,method=simpson)):a9:=evalf(ApproximateInt(A9*(g3*g3 ) ,theta=a..1,method=simpson)) :a10:=evalf(A10*ApproximateInt(g3*g3,theta=a..1,method=simpson)):a11:=evalf(ApproximateInt(1,theta=a..1,method=simpson)):a12:=evalf(ApproximateInt(1*(1-1/2 (1)),theta=a..1,method=simpson)):dsys3 := { f3(x)*(a1)+ f3(x)*(a2) +((&DifferentialD;)^2)/((&DifferentialD;x)^2) f3(x)*(a3) +f3(x)*a4+ f3(x)*(a5) +((&DifferentialD;)^2)/((&DifferentialD;x)^2) f3(x)*(a6) +f3(x)*a7= ((&DifferentialD;)^2)/((&DifferentialD;x)^2) f3(x) *(a8) + a9*(&DifferentialD;)/(&DifferentialD;x) f3(x) +f3(x)*a10+ a11+a12 , f3(1) =0,f3(0) =0 , D^(1)(f3)(1) = 0, D^(1)(f3)(0)=0,D^(3)(f3)(1) = 0, D^(3)(f3)(0)=0} :dsol5 := dsolve(dsys3, 'maxmesh'=2024, numeric,abserr=.0001, range=0..1, output=listprocedure):fy3:= eval(f3(x),dsol5):with(CurveFitting):fy33:=PolynomialInterpolation([[0,fy3(0)],[.1,fy3(0.1)],[.2,fy3(0.2)],[0.3,fy3(0.3)],[.4,fy3(0.4)],[.5,fy3(0.5)],[0.6,fy3(0.6)],[0.7,fy3(0.7)],[0.8,fy3(0.8)],[0.9,fy3(0.9)],[1,fy3(1)]],x): d1:=A1*ApproximateInt(((&DifferentialD;)^6)/((&DifferentialD;x)^6)fy33*fy33,x=a..1,method=simpson) :d2:= A2*ApproximateInt(((&DifferentialD;)^4)/((&DifferentialD;x)^4)fy33*fy33 ,x=a..1,method=simpson) :d3:=A3*ApproximateInt(((&DifferentialD;)^2)/((&DifferentialD;x)^2)fy33*fy33,x=a..1,method=simpson): d4:= A4*ApproximateInt(fy33*fy33,x=a..1,method=simpson):d5:=A5*ApproximateInt(((&DifferentialD;)^4)/((&DifferentialD;x)^4)fy33*fy33,x=a..1,method=simpson) : d6:=A6*ApproximateInt(((&DifferentialD;)^2)/((&DifferentialD;x)^2)fy33*fy33,x=a..1,method=simpson) :d7:=A7*ApproximateInt(fy33*fy33,x=a..1,method=simpson) :d8:=A8*ApproximateInt(((&DifferentialD;)^2)/((&DifferentialD;x)^2)fy33*fy33,x=a..1,method=simpson) :d9:=ApproximateInt(A9*(((&DifferentialD;)^1)/((&DifferentialD;x)^1)fy33*fy33 ) ,x=a..1,method=simpson) :d10:=A10*ApproximateInt(fy33*fy33,x=a..1,method=simpson) :d11:=evalf(ApproximateInt(1,theta=a..1,method=simpson)):d12:=evalf(ApproximateInt(1*(1-1/2 (1)),theta=a..1,method=simpson)) : d sys4 := { h3(theta)*(d1)+((&DifferentialD;)^2)/((&DifferentialD;theta)^2) h3(theta)*(d2)+((&DifferentialD;)^4)/((&DifferentialD;theta)^4) h3(theta)*(d3)+ ((&DifferentialD;)^6)/((&DifferentialD;theta)^6) h3(theta)*(d4)+h3(theta) *(d5)+ h3(theta) *(d6) +((&DifferentialD;)^4)/((&DifferentialD;theta)^4) h3(theta)*(d7)= h3(theta)*(d8) +d9*(&DifferentialD;)/(&DifferentialD;theta) h3(theta) +((&DifferentialD;)^2)/((&DifferentialD;theta)^2) h3(theta)*(d10) +d11+d12 ,h3(1) = 0,h3(0) = 0 , D^(1)(h3)(1) = 0, D^(1)(h3)(0)=0,D^(3)(h3)(1) = 0, D^(3)(h3)(0)=0} :dsol6 := dsolve(dsys4, 'maxmesh'=2024, abserr=.0001, range=0..1, numeric, output=listprocedure):g33:= eval(h3(theta),dsol6):with(CurveFitting):g3:=PolynomialInterpolation([[0,g33(0)],[.1,g33(0.1)],[.2,g33(0.2)],[0.3,g33(0.3)],[.4,g33(0.4)],[.5,g33(0.5)],[0.6,g33(0.6)],[0.7,g33(0.7)],[0.8,g33(0.8)],[0.9,g33(0.9)],[1,g33(1)]],theta):"

  

 

``

 

Download PLATE.mw

How to determine eigenvalues?...

Asked by: torabi 90
linear-algebra eigenvalues parametric
May 13 2016
0  4

hi.how i can determind  eignvalue of matrix in the form parametric?

thanks1.mw

T := Matrix(5, 5, {(1, 1) = -b*beta*k/(c*u)-d, (1, 2) = 0, (1, 3) = -beta*lambda*c*u/(b*beta*k+c*d*u), (1, 4) = 0, (1, 5) = 0, (2, 1) = b*beta*k/(c*u), (2, 2) = -s*(lambda*c*k*beta/(b*beta*k+c*d*u)-a)/P-a, (2, 3) = beta*lambda*c*u/(b*beta*k+c*d*u), (2, 4) = -s*b/c, (2, 5) = r*(s-p)/s, (3, 1) = 0, (3, 2) = k, (3, 3) = -u, (3, 4) = 0, (3, 5) = 0, (4, 1) = 0, (4, 2) = -s*(lambda*c*k*beta/(b*beta*k+c*d*u)-a)/P, (4, 3) = 0, (4, 4) = -s*b/c-b, (4, 5) = r*(s+c)/s, (5, 1) = 0, (5, 2) = s*(lambda*c*k*beta/(b*beta*k+c*d*u)-a)/P, (5, 3) = 0, (5, 4) = s*b/c, (5, 5) = -r})

Matrix(5, 5, {(1, 1) = -b*beta*k/(c*u)-d, (1, 2) = 0, (1, 3) = -beta*lambda*c*u/(b*beta*k+c*d*u), (1, 4) = 0, (1, 5) = 0, (2, 1) = b*beta*k/(c*u), (2, 2) = -s*(lambda*c*k*beta/(b*beta*k+c*d*u)-a)/P-a, (2, 3) = beta*lambda*c*u/(b*beta*k+c*d*u), (2, 4) = -s*b/c, (2, 5) = r*(s-p)/s, (3, 1) = 0, (3, 2) = k, (3, 3) = -u, (3, 4) = 0, (3, 5) = 0, (4, 1) = 0, (4, 2) = -s*(lambda*c*k*beta/(b*beta*k+c*d*u)-a)/P, (4, 3) = 0, (4, 4) = -s*b/c-b, (4, 5) = r*(s+c)/s, (5, 1) = 0, (5, 2) = s*(lambda*c*k*beta/(b*beta*k+c*d*u)-a)/P, (5, 3) = 0, (5, 4) = s*b/c, (5, 5) = -r})

 (1)

``

 

Download 1.mw

 

How to convert ODE system to differential form?...

Asked by: LeeHoYeung 535
ode differentialgeometry
May 11 2016
0  0

how to convert system of differential equations to differential form for evalDG?

 

[a(t)*(diff(c(t), t))+b(t), a(t)*(diff(b(t), t))+c(t)*(diff(b(t), t)), a(t)*(diff(c(t), t))+a(t)*(diff(b(t), t))+b(t)];

when i try eliminate dt which is the denominator

eliminate([a(t)*dc(t) + b(t)*dt,a(t)*db(t)+dt*c(t)*db(t),a(t)*dc(t)+a(t)*db(t)+b(t)*dt],dt);

[{dt = -a(t)/c(t)}, {a(t)*(c(t)*dc(t)-b(t)), a(t)*(db(t)*c(t)+c(t)*dc(t)-b(t))}]

 

i got two solutions, which one is correct?

a(t)*(c(t)*dc(t)-b(t)), a(t)*(db(t)*c(t)+c(t)*dc(t)-b(t))

does it mean that two have to use together to form a differential form?

 

update1

with(DifferentialGeometry):
DGsetup([a,b,c], M);
X := evalDG({a*(c*D_c-b), a*(D_b*c+c*D_c-b(t))});
Flow(X,t);
Flow(X, t, ode = true);

got error when run with above result

 

How to solve it?...

Asked by: torabi 90
fsolve
April 30 2016
1  15

hi.i am a problem for solving this non linear algebric equation.

please help me...thanks

FSOLVE.mw

FSOLVE.mw

 

Default method used in pdsolve/numeric...

Asked by: Al86 150
numeric pdsolve
April 27 2016
2  0

I read in the net that the method used in pdsolve numeric is the theta method, my question: is it the most efficient with regard to rate of convergence of the numerical solution of the PDE?

If not then why is it used as the default method?

 

Thanks.

 

How to find eigenvectors in terms of mmm?...

Asked by: LeeHoYeung 535
eigenvectors
April 27 2016
0  2

nullspace or reducedform or Eigenvectors still can not find eigenvector in terms of  mmm , how to find this?

 

mmm is a variable

How to use generate_ic for this case?...

Asked by: LeeHoYeung 535
detools ic
April 25 2016
0  0

H2 := [a(t)*(diff(c(t), t))+b(t) = 100, a(t)*(diff(b(t), t))+c(t)*(diff(b(t), t)) = exp(t), a(t)*(diff(c(t), t))+a(t)*(diff(b(t), t))+b(t) = 90];
H1 := subs([diff(a(t),t)=a1,diff(b(t),t)=b1,diff(c(t),t)=c1], H2);
H := subs([a(t)=a0, b(t)=b0, c(t)=c0], H1);
ics := generate_ic(H, {a0=-2..2, b0=-2..2, c0=-2..2,a1 = -2 .. 2, b1 = -2 .. 2, c1 = -2 .. 2, t = 0, energy = 0}, 100);

 

Error, (in generate_ic) invalid input: `DEtools/generate_ic` expects its 1st argument, H, to be of type algebraic, but received [a0*c1+b0 = 100, a0*b1+c0*b1 = exp(t), a0*c1+a0*b1+b0 = 90]

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