This is most likely a simple question for the power users of this forum, but I do not manage to find a solution. I have date in an Excel file. The first column consists of dates (mm/dd/yyyy) and the second of time (hh:mm). I can easily concatenate both in Maple using cat("9/7/2023", "10:22") but how can I convert the obtained string into a date+time that Maple understands? 

Thank you in advance for your help.

Below is the plot like I want it. The basic plot has been done with a simple plot command.

>plot(0, x = 0 .. 10, y = 0 .. 4, gridlines = true)

But the label of each axis was done manually. But I have tried to do it inside the plot command. A little help would be very appreciated.

So here is what I want the plot to look like:

Thank you in advance for the help.

Mario

Hi everyone,

Do you know if there are some known codes for plotting pseudospectra of squared (and finite) matrices with given spectrum ? 
Thanks in advance

Best,

Rachid

What will be the range of p and q to get the plot and to get the optimum solution?
If possible get a solution for particular value of p and q.
file attached: q1.mw

Hi all, any one help  me to find the values of constants by using given condition and then how to varify that the goiven condition varify the expression. I have found manually but want to varify through maple.

help.mw

I have a list:
mylist := [x^4 + (-4*m - 7)*x^3 + (m + 4)*x^2 + (3*m - 5)*x, x^4 + (-4*m - 7)*x^3 + (m + 5)*x^2 + (5*m - 7)*x, x^4 + (-4*m - 7)*x^3 + (m + 5)*x^2 + (7*m - 5)*x, x^4 + (-4*m - 7)*x^3 + (2*m + 5)*x^2 + (3*m - 5)*x, x^4 + (-4*m - 7)*x^3 + (3*m + 1)*x^2 + (7*m - 10)*x, x^4 + (-4*m - 5)*x^3 + (2*m + 1)*x^2 + (7*m - 9)*x]

I use

L := map~(normal, mylist);

and get. 

L := [x^4 - (4*m + 7)*x^3 + (m + 4)*x^2 + (3*m - 5)*x, x^4 - (4*m + 7)*x^3 + (m + 5)*x^2 + (5*m - 7)*x, x^4 - (4*m + 7)*x^3 + (m + 5)*x^2 + (7*m - 5)*x, x^4 - (4*m + 7)*x^3 + (2*m + 5)*x^2 + (3*m - 5)*x, x^4 - (4*m + 7)*x^3 + (3*m + 1)*x^2 + (7*m - 10)*x, x^4 - (4*m + 5)*x^3 + (2*m + 1)*x^2 + (7*m - 9)*x].

I use seq to list L[i] and diff(L[i])

[seq([L[i], diff(L[i], x)], i = 1 .. nops(L))];

and get

[[x^4 - (4*m + 7)*x^3 + (m + 4)*x^2 + (3*m - 5)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(m + 4)*x + 3*m - 5], [x^4 - (4*m + 7)*x^3 + (m + 5)*x^2 + (5*m - 7)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(m + 5)*x + 5*m - 7], [x^4 - (4*m + 7)*x^3 + (m + 5)*x^2 + (7*m - 5)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(m + 5)*x + 7*m - 5], [x^4 - (4*m + 7)*x^3 + (2*m + 5)*x^2 + (3*m - 5)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(2*m + 5)*x + 3*m - 5], [x^4 - (4*m + 7)*x^3 + (3*m + 1)*x^2 + (7*m - 10)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(3*m + 1)*x + 7*m - 10], [x^4 - (4*m + 5)*x^3 + (2*m + 1)*x^2 + (7*m - 9)*x, 4*x^3 - 3*(4*m + 5)*x^2 + 2*(2*m + 1)*x + 7*m - 9]]

How can I insert L'(2), L''(2) and solve the systems L'(2) = 0 and L''(2) > 0 to get the solutions m?
like this
[seq([L[i], diff(L[i], x), solve([L'(2) = 0,L''(2)>0],m) ], i = 1 .. nops(L))]

I also tried
[seq([L[i], diff(L[i], x), eval(diff(L[i], x), x = 2), solve([eval(diff(L[i], x), x = 2) = 0], m)], i = 1 .. nops(L))]

to obtain 
[[x^4 - (4*m + 7)*x^3 + (m + 4)*x^2 + (3*m - 5)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(m + 4)*x + 3*m - 5, -41 - 41*m, {m = -1}], [x^4 - (4*m + 7)*x^3 + (m + 5)*x^2 + (5*m - 7)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(m + 5)*x + 5*m - 7, -39 - 39*m, {m = -1}], [x^4 - (4*m + 7)*x^3 + (m + 5)*x^2 + (7*m - 5)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(m + 5)*x + 7*m - 5, -37 - 37*m, {m = -1}], [x^4 - (4*m + 7)*x^3 + (2*m + 5)*x^2 + (3*m - 5)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(2*m + 5)*x + 3*m - 5, -37 - 37*m, {m = -1}], [x^4 - (4*m + 7)*x^3 + (3*m + 1)*x^2 + (7*m - 10)*x, 4*x^3 - 3*(4*m + 7)*x^2 + 2*(3*m + 1)*x + 7*m - 10, -58 - 29*m, {m = -2}], [x^4 - (4*m + 5)*x^3 + (2*m + 1)*x^2 + (7*m - 9)*x, 4*x^3 - 3*(4*m + 5)*x^2 + 2*(2*m + 1)*x + 7*m - 9, -33 - 33*m, {m = -1}]]

I need to extract the list of all powers present in multivariable polynomial. For example, for x+y+x^2y^2+y^d I want to get the list [(1,0),(0,1),(2,2),(0,d)]. How to perform this?

Hello Everyone;

I need help to solve the following system using rk-4 method

restart;
NULL;
NULL;
C := 1.0;
gK := 36.0;
gNa := 120.0;
gL := 0.3;
VK := -77.0;
VNa := 50.0;
VL := -54.0;
III := 20;
alpha_n := 0.01*(v(t) + 55.0)/(1 - exp(-1.0/10.0*v(t) - 11.0/2.0));
beta_n := 0.125*exp((-v(t))/80.0 + (-1)*13.0/16.0);
alpha_m := 0.1*(v(t) + 40.0)/(1 - exp(-1.0/10.0*v(t) - 4.0));
beta_m := 4.0*exp(-1.0/18.0*v(t) - 65.0/18.0);
alpha_h := 0.07*exp((-1)*(v(t) + 65.0)/20.0);
beta_h := 1/(1.0 + exp((-v(t) + 35.0)/10.0));

dsys1 := {diff(h(t), t) = alpha_h*(1 - h(t)) - beta_h*h(t), diff(m(t), t) = alpha_m*(1 - m(t)) - beta_m*m(t), diff(n(t), t) = alpha_n*(1 - n(t)) - beta_n(t), diff(v(t), t) = III - gK*n(t)^4*(v(t) - VK) - gNa*m(t)^3*h(t)*(v(t) - VNa) - gL*(v(t) - VL), h(0) = 0.9996937394, m(0) = 0.02890553447, n(0) = 0.2445865495, v(0) = -70};

modifed_practice.mw

Impact of Shape-Dependent Hybrid Nanofluid on Transient Efficiency of a Fully W
et Porous Longitudinal Fin

dear sir please help me to solve the graph i given reference pdf also. i have implimented the code but getting error in ploting 

Thank you

Using the SingularValues command with any output type specified causes this error

Error, (in sanity) invalid input: LinearAlgebra:-SingularValues expects value for keyword parameter output to be of type {list(identical(U,S,Vt,list)), identical(U,S,Vt,list)}, but received [U, S, Vt]

Below is a minimal example to trigger the error. Is there something wrong about how I am calling the function?

restart:
with(LinearAlgebra):

sanity := proc()
  local A,U,S,Vt;
  A :=RandomMatrix(3,10);
  U,S,Vt := SingularValues(A, output=['U','S','Vt']);
end proc:

sanity();

Dear Maple experts,

I have a system of several nonlinear equaitons. My code can solve it for a given parameter. But when I want to plot it, it takes too much time with no results. So, I decided to plot it for several given points. I get the answer for the points individually, but I don't know how to apply this to 'plot' command. Would you please help?

Download Reza_Tchno_(v3).mw

Besdies, it seems for some points there is no feasible solution. So, there is no need to have plot for them.

I attach the code. Thank you so much!

dS/dt=qnv-alpha_1*S*H-mu_sh*S

dH/dt=lamda_h-alpha_1*S*H-mu_h*H

dI/dt=alpha_1*S*H-beta_1*I-mu_i*I

dS/dt=beta_1*I-delta_1*S-mu_s*S

DATA:

q=0.75; n=15;v=20; alpha_You1=0.001; S=2000; H=3000; mu_sh=0.000000000012; lambda=3000;mu_h=0.94; beta_1=0.125; I=0; mi_i=0.95; delta_1=0.0975; S=0; mu_s=0.029