Maple 18 Questions and Posts

These are Posts and Questions associated with the product, Maple 18

Hi maple users 

I am working with the PDE solver.

i am receiving a following error

"unable to compute solution for t>HFloat(0.0):" 

Kindly do the needful how to rectify this error.

How can we determine the highest (or peak) value for every hump and at what value of (x, t) in the plot?

How to find the dispersion relation (3) in Maple? I try it by equating the coefficients of cos(kx + wt) and its derivative to zero, but couldn't find it.



alias(E = E(x, t), P = P(x, t), N = N(x, t), Q = Q(x, t));

E, P, N, Q


d := Matrix([[c*(diff(E, t))+diff(E, x), alpha*P, 0, 0], [N[0]*E, diff(P, t), -sigma[2]*Q[0]*N/N[0], sigma[2]*omega[0]*Q], [0, sigma[1]*sigma[2]*Q[0]*P/N[0], diff(N, t), 0], [0, -omega[0]*P, 0, diff(Q, t)]]) = 0

d := (Matrix(4, 4, {(1, 1) = c*(diff(E(x, t), t))+diff(E(x, t), x), (1, 2) = alpha*P(x, t), (1, 3) = 0, (1, 4) = 0, (2, 1) = N(x, t)[0]*E(x, t), (2, 2) = diff(P(x, t), t), (2, 3) = -sigma[2]*Q(x, t)[0]*N(x, t)/N(x, t)[0], (2, 4) = sigma[2]*omega[0]*Q(x, t), (3, 1) = 0, (3, 2) = sigma[1]*sigma[2]*Q(x, t)[0]*P(x, t)/N(x, t)[0], (3, 3) = diff(N(x, t), t), (3, 4) = 0, (4, 1) = 0, (4, 2) = -omega[0]*P(x, t), (4, 3) = 0, (4, 4) = diff(Q(x, t), t)})) = 0


re := -c*omega^3-kappa*omega^2+(c*omega[0]*(N[0]^2*sigma[2]+Q[0]^2*sigma[1])/N[0]^2-alpha*N[0])*omega+kappa*omega[0]*(N[0]^2*sigma[2]+Q[0]^2*sigma[1])/N[0]^2 = 0;

-c*omega^3-kappa*omega^2+(c*omega[0]*(Q[0]^2*sigma[1]+N[0]^2*sigma[2])/N[0]^2-alpha*N[0])*omega+kappa*omega[0]*(Q[0]^2*sigma[1]+N[0]^2*sigma[2])/N[0]^2 = 0





alias(u = u(x, y, z, t), f = f(x, y, z, t));
                              u, f
u := (diff(f, y, x, x, x, x))*f^4-(diff(f, x, x, x, x))*(diff(f, y))*f^3-4*(diff(f, y, x, x, x))*(diff(f, x))*f^3+8*(diff(f, x, x, x))*(diff(f, x))*(diff(f, y))*f^2-4*(diff(f, x, x, x))*(diff(f, y, x))*f^3+12*(diff(f, y, x, x))*(diff(f, x))^2*f^2-36*(diff(f, x, x))*(diff(f, x))^2*(diff(f, y))*f+24*(diff(f, x, x))*(diff(f, x))*(diff(f, y, x))*f^2-6*(diff(f, x, x))*(diff(f, y, x, x))*f^3+6*(diff(f, x, x))^2*(diff(f, y))*f^2-24*(diff(f, x))^3*(diff(f, y, x))*f+24*(diff(f, x))^4*(diff(f, y))+2*(diff(f, y, x, t))*f^4-2*(diff(f, y, x))*(diff(f, t))*f^3-2*(diff(f, x, t))*(diff(f, y))*f^3+4*(diff(f, x))*(diff(f, y))*(diff(f, t))*f^2-2*(diff(f, x))*(diff(f, y, t))*f^3-3*(diff(f, z, x, x))*f^4+3*(diff(f, x, x))*(diff(f, z))*f^3+6*(diff(f, x))*(diff(f, z, x))*f^3-6*(diff(f, x))^2*(diff(f, z))*f^2;

Please how  can I use getdata to extract only 200x2 of 208x2 matrix from maple to excel.

For instance I have:

Q:= ( seq( seq( plottools:-getdata(ans1[s1,3])[j,3],j=1..3), s1=1));

It returns  208x2,  200x2 200x2 matrices and I can't extract it using 

`<|>`( seq( seq( plottools:-getdata(ans1[s1,3])[j,3],j=1..3), s1=1));

because the matrices have different dimension. Please, how can make 208x2 matrix to 200x2?

Hi, please how do I delete only the 0*I of the complex expression: 0.*I - 3?

I tried this:  remove(`=`, [0.*I-3, 5, 7, -2], 0.*I);

But couldn't work.

How to linearize eq (6) by neglecting all higher order terms i.e., epsilon[1]^2, epsilon[2]^2, epsilon[1]*epsilon[2]... etc? How to do it in maple?

How to find values of w for which determinant of A is zero?

I want to change the colors of a contour such that the region above zero is represented by a different color instead of yellow color,  and that the colors for conts <0 are one set of colors (maybe yellow to red), and the area for which conts >0 is one color which is very different from the others (so maybe white).


I wanna export data from maple to excel and I tried this:

ExcelTools:-Export(op([1, 1], plots:-display( convert( ans1[12..14,3], list))));

I was expecting 4 columns including z vector and 3 columns from ans1[12..14,3] but got only 2

Please any help?

Please, how do I use surface or contour to plot discontinous function?

z = f(x,y) := x-.8193318913*sin(x)*cos(x)/(cos(x)^2+sinh(y)^2)-(0.2931044702e-2*(0.7500000000e-3*x^2-0.7500000000e-3*y^2+0.1622336517e-1))*sin(x)*cos(x)/(((0.7500000000e-3*x^2-0.7500000000e-3*y^2+0.1622336517e-1)^2+0.2250000000e-5*x^2*y^2)*(cos(x)^2+sinh(y)^2))-0.4396567053e-5*x*y*sinh(y)*cosh(y)/(((0.7500000000e-3*x^2-0.7500000000e-3*y^2+0.1622336517e-1)^2+0.2250000000e-5*x^2*y^2)*(cos(x)^2+sinh(y)^2)):

The matrix data[gridji,4] in my code has float undefined. Please, how do I handle it?

Can we convert expression into determinant of 3 rows and 3 columns?

Can we write v matrix in terms of matrix u? i.e., v=const*u.

We have the system with one discrete variable along x-axis (i.e. 'i' is discrete in the attached file) and other variable 't' is continuous. But maple return error.

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