Dear all,

consider two lists of complex values :

list1 := [l1,l2,l3,l4,l5]

list2 := [s1,s2,s3,s4,s5].

There is a set of second order differential equation

d^2u(k)/dt^2+I*A*du/dt-B*u=0

where A is sum of elements of list1 and list2 and B is multiplication of their element. Therefore,

d^2u[1](k)/dt^2+I*(l1+s1)*du[1]/dt-(l1*s1)*u[1]=0

d^2u[2](k)/dt^2+I*(l2+s2)*du[2]/dt-(l2*s2)*u[2]=0

d^2u[3](k)/dt^2+I*(l3+s3)*du[3]/dt-(l3*s3)*u[3]=0

d^2u[4](k)/dt^2+I*(l4+s4)*du[4]/dt-(l4*s4)*u[4]=0

d^2u[5](k)/dt^2+I*(l5+s5)*du[5]/dt-(l5*s5)*u[5]=0

How can I create a set of differential equations and initial conditions based on nops(list1), then solve this system of differential equations numerically in Maple.

since u[i] are function of k, next step is to transforme them to real space by inverse fourier transform.

finally save the results and plot them.

Note that for simplisity I wrote a linear equation but it is not. so, because of nonlinear terms it is not possible to use superposition of the solution. I have to take them as coupled system of equations.

====

for example

list1 := [ [0., -5.496799068*10^(-15)-0.*I], [.1, 5.201897725*10^(-16)-1.188994754*I], [.2, 6.924043163*10^(-17)-4.747763855*I], [.3, 2.297497722*10^(-17)-10.66272177*I], [.4, 1.159126178*10^(-17)-18.96299588*I] ] 

list2 :=[ [0., -8.634351786*10^(-7)-67.81404036*I], [.1, -0.7387644021e-5-67.76491234*I], [.2, -0.1433025271e-4-67.59922295*I], [.3, -0.2231598645e-4-67.25152449*I], [.4, -0.3280855430e-4-66.56357035*I] ]

where first element is k and the second value is l_i and s_i

the differential equation is

ode_u[i]:= diff(u[i](t),t$2)+I*(list1[i][2]+list2[i][2])*diff(u[i](t),t)-list1[1][2]*list2[2][2]*u[i](t)=0;

eta is in fourier space where k values are in list1[i][1].

We laso know that f(-k)= - f*(k) where f=list[i][2]

and u[i] as function of k, initially has a Gaussian shape at t=0 in fourier space..

Thanks in advance for your help

Anyone out there converted the  nyqlog at MATLAB/nyqlog.m at master · nielsSkov/MATLAB · GitHub  to Maple or Maple Flow? For Nyquist plots...

Bonjour, petite question simple que je me pose la MapleSim permet de tout réaliser ?

Hello everyone ! 

I am completely new to using math solving applications like maple.

I was introduced to it in my university course and since then I found it very helpful in solving 2nd degree differential equations and integrals.

However, i don't have any intuition for programming, so i found the commands of maple very confusing.

The last couple of weeks, I have been completely destroyed by a problem I've recently encountered...

I was given a bunch of (x,y) coordinates of a function and i was told that the function in question is a polynomial of a 3rd degree.

So my question is, can maple help me in solving this type of problems or no ?!?!?!

And if yes, can someone give me a general direction in which i have to go ?

Also, I was told that this problem can be solved in Excel ?

Thank you all in adavce ! 

Looking for the solution of this a non linear system y = x^2 + 2*x - 3 ,  y = x^3 + 3*x^2 - 4*x - 8 (The system has 3 real solutions A = (-3.35, 1.51)    B = (-0.72, -3.92)  C = (2.07, 5.42) ).

i have tried to solve it as follows:

eq1 := x^2 + 2*x - 3

eq2 := x^3 + 3*x^2 - 4*x - 8

fsolve({eq1 = eq2})

I get 

   {x = -3.346462190}, {x = -0.7222456338}, {x = 2.068707823}

That is what i expected.
 

But if i try to use solve and then evalf i find three complex solutions.

solution := solve({eq1 = eq2}, explicit)

evalf(%);
      
  { x = 2.068707824 - 4x10^(-10)   I },     { x = -3.346462190 - 7.660254040 x10^(-10)    I },   { x = -0.722245634 + 9.660254040x10^(-10)    I }
    

Why ? I don't understand.

Moreover, solving the equations as follows:
sys1 := y = x^2 + 2*x - 3;
sys2 := y = x^3 + 3*x^2 - 4*x - 8;

fsolve({sys1, sys2}, {x, y})

yeld just one solution:

               {x = 2.068707823, y = 5.416967705}

Someone can explain me this behaviour ?

Dear Users,

I hope everyone here is fine. I want to extract dat file from the attached contour plot file. Please help me to resolve this issue. Many thanks in advance

Dat_file.mw

restart:
PDEtools[declare](f(x), prime = x):
PDEtools[declare](Theta(x), prime = x):
PDEtools[declare](Phi(x), prime = x):
N := 4; M := .1; Kp := .1; Gr := 0.1e-1; Gc := 0.1e-1; Pr := 1; S := 0.1e-1; Sc := .78; Kc := 0.1e-1; La := 1
f (x):=  sum((p^(i))*f [i] (x), i = 0 .. N) ;
Theta(x):=  sum((p^(i))*Theta[i] (x), i = 0 .. N) ;
Phi(x):= sum((p^(i))*Phi [i] (x), i = 0 .. N);
HPMEq1 := (1-p)*(diff(f(x), x, x, x))+p*(diff(f(x), x, x, x)+(1/2)*(diff(f(x), x, x))*f(x)-(M^2+Kp)*(diff(f(x), x)-La)+Gr*Theta(x)+Gc*Phi(x))
HPMEq2 := (1-p)*(diff(Theta(x), x, x))/Pr+p*((diff(Theta(x), x, x))/Pr+(1/2)*(diff(Theta(x), x))*f(x)+S*Theta(x))
HPMEq3 := (1-p)*(diff(Phi(x), x, x))/Sc+p*((diff(Phi(x), x, x))/Sc+(1/2)*(diff(Phi(x), x))*f(x)+Kc*Phi(x))
for i from 0 to N do equ[1][i] := coeff(HPMEq1, p, i) = 0 end do
for i from 0 to N do equ[1][i] := coeff(HPMEq2, p, i) = 0 end do
for i from 0 to N do equ[1][i] := coeff(HPMEq3, p, i) = 0 end do
cond[1][0] := f[0](0) = 0, (D(f[0]))(0) = 0, Theta[0](0) = 1, Phi[0](0) = 1, Theta[0](5) = 0, Phi[0](5) = 0, (D(f[0]))(5) = 1; for j to N do cond[1][j] := f[j](0) = 0, (D(f[j]))(0) = 0, Theta[j](0) = 0, Phi[j](0) = 0, Theta[j](5) = 0, Phi[j](5) = 0, (D(f[j]))(5) = 0 end do
for i from 0 to N do pdsolve({cond[1][i], equ[1][i]}, f[i](x)); f[i](x) := rhs(%) end do
f(x) := evalf(simplify(sum(f[n](x), n = 0 .. N))); convert(f(x), 'rational'); subs(x = 1, diff(f(x), x))

Please rectify the error
Thank you

Error, (in PD/PD) too many levels of recursion

Maple Input:
restart; with(RealDomain); log[2](x^2 - 6*x) = 3 + log[2](1 - x); Maple returns as solution
ln\x - 6 x/ ln(1 - x) ------------ = 3 + --------- ln(2) ln(2) "(->)" [[x = 2], [x = -4]]
Is the solution x = 2 correct?

Substituting x=2 into the original Function Maple returns correct: log[2](2^2 - 6*2);

undefined and log[2](1 - 2).; undefined. So x =2 should not be a solution of this function.

Hi,

I am trying to automatically combine plots that I created with an index: ex. IP[i] := plot(...

I can combine them manually, but the maximum value of i can be almost any number greater than 1, and I don’t want to edit things all the time. i can also be very big. I have tried several random ways of embedding the index, but I’ve had no success.

Any ideas? Thanks.

Jno.

Please Help!  The flow gets me like this,Where should i fix this problem.The flow changes for me fluctuate through the series range.What to do to get upflow in f(eta) and downflow in theta(eta)

 MVP.mw

I want to import a numeric 2800*1 matrix from matlab to maple by following command, but faced error as bellow:

X := ImportMatrix("E:/.../Omega.mat", source = MATLAB);
 ImportMatrix:-ModuleApply called with arguments: E:/.../Omega.mat, datatype = auto, delimiter = (), format = (), mode = (), output = all, ragged = true, skiplines = 0, source = MATLAB, sourceid = all, transpose = false
 #(ImportMatrix:-ModuleApply,36): error
Error, (in ImportMatrix) Array index out of range
 locals defined as: file = E:/.../Omega.mat, src = Matlab, ext = ext, res = res, x = x, isv7 = isv7, del = false

Where is the problem?

How to import?

This is my current code:

with~([NumberTheory, DocumentTools]):
tb := Tabulate([seq]([galois](CyclotomicPolynomial(i, x),x), i = 1 .. 10)):

I hope to export it into SVG file, but this code will report a error information:

Export("aatest.svg", tb)

# this is an example:

with(plots);

A := [[[6, 13], [6, 7], [5, 7], [5, 5], [7, 5], [7, 4], [4, 4], [4, 13]], [[13, 13], [13, 20], [20, 20], [20, 23], [22, 23], [22, 22], [23, 22], [23, 16], [16, 16], [16, 9], [9, 9], [9, 6], [7, 6], [7, 7], [6, 7], [6, 13]], [[13, 23], [20, 23], [20, 20], [13, 20]], [[13, 24], [20, 24], [20, 23], [13, 23]], [[22, 24], [22, 23], [20, 23], [20, 24]], [[24, 24], [24, 22], [23, 22], [23, 23], [22, 23], [22, 24]], [[22, 22], [22, 23], [23, 23], [23, 22]], [[22, 25], [25, 25], [25, 16], [23, 16], [23, 22], [24, 22], [24, 24], [22, 24]], [[25, 6], [16, 6], [16, 9], [23, 9], [23, 16], [25, 16]], [[9, 6], [9, 9], [16, 9], [16, 6]], [[6, 6], [6, 7], [7, 7], [7, 6]], [[6, 20], [13, 20], [13, 13], [6, 13]], [[20, 28], [28, 28], [28, 16], [25, 16], [25, 25], [22, 25], [22, 24], [20, 24]], [[16, 5], [9, 5], [9, 6], [16, 6]], [[7, 5], [7, 6], [9, 6], [9, 5]], [[5, 5], [5, 7], [6, 7], [6, 6], [7, 6], [7, 5]], [[4, 23], [13, 23], [13, 20], [6, 20], [6, 13], [4, 13]], [[23, 9], [16, 9], [16, 16], [23, 16]], [[9, 1], [1, 1], [1, 13], [4, 13], [4, 4], [7, 4], [7, 5], [9, 5]]];
NULL;

arte := seq(polygonplot([A[i]], color = ColorTools:-Color([rand()/10^12, rand()/10^12, rand()/10^12]), axes = none, style = polygon, view = [1 .. max(A[]), 1 .. max(A[][])]), i = 1 .. nops(A));
display(arte);