Dear friends, please I would like to ask for your help with the following situation: 

Suppose I have an Array   A:=Array([4]);   and I have to take the element A[i], add 1 to it and then append it to A, with i = 1..3. The result would be, 

A:= [4 5 6 7] 

I do know how to perform the task with a for loop, however I know that for large i it is more advisable to use seq for speed reasons.   I cannot find the right syntax to perform such a task with seq. Could you please advise me how to do so? 

Many thanks for your help. 

Dear all

I have data and a vector d. 
I would like to sum the elements of the vector d corresponding to the index  of the element data <=0.01 

Step 1: we select the index of data that corresponds to data<=0.01

step 2: we select the consecutive index corresponding to data<=0.01

Step 3 : we sum the element of d corresponding to the previous index

step 4: update d=d/number(index) ;

Please see my attached code. It's done by hand how can reformulate the code.

code_vector.mw

many thanks

DATA.pdf

I keep getting errors empty sets or only header information using the HTTP or URL package to when trying to download files from here through Maple. 

How do I download the csv files from here?
https://github.com/CSSEGISandData/COVID-19/tree/master/csse_covid_19_data/csse_covid_19_time_series

How do I know that what numerical method has maple used in this code.?

dsolve({eq11,eq21,eq3,eq4,bc21,bc22},numeric,continuation=lambda1,maxmesh=15000, output=array([seq( i, i=0..N,0.01 )]))

     Dear Sir/Madam,

I have faced a problem while using Maple 18. The  warning is the following

Warning, The use of global variables in numerical ODE problems is deprecated, and will be removed in a future release. Use the 'parameters' argument instead (see ?dsolve,numeric,parameters)

This is the code

restart;
with(plots);
beta := 0.2e-1; delta := .5; PI := 10000; mu := 0.16e-1; tau := 0.3e-1; rho := 0.4e-1; epsilon := 0.4e-1; sigma[1] := 0.1e-2; sigma[2] := 0.2e-2; eta := 0.6e-1;
sys := {diff(e(t), t) = beta*(sigma[1]*i(t)+sigma[2]*e(t))*s(t)-(delta+mu)*e(t), diff(i(t), t) = tau*delta*e(t)-(epsilon+rho+mu)*i*t, diff(r(t), t) = (1-tau)*delta*e(t)+epsilon*i(t)-(mu+eta)*r(t), diff(s(t), t) = PI+eta*r(t)-beta*(sigma[1]*i(t)+sigma[2]*e(t))*s(t)-mu*s(t), e(0) = 148, i(0) = 74, r(0) = 14, s(0) = 4110};
p1 := dsolve(sys, numeric, method = rkf45, output = procedurelist);
Warning, The use of global variables in numerical ODE problems is deprecated, and will be removed in a future release. Use the 'parameters' argument instead (see ?dsolve,numeric,parameters)
Error, (in dsolve/numeric) i(t) and i cannot both appear in the given ODE
p2o := odeplot(p1, [t, s(t)], 0 .. 4, numpoints = 100, labels = ["Time (months)", " Infected  "], labeldirections = [horizontal, vertical], style = line, color = red, axes = boxed);
Error, (in plots/odeplot) input is not a valid dsolve/numeric solution

plots[display](p2o);

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/nnn.mw .

Download nnn.mw

If we have an equation for the generalized Bloch sphere i.e.,

\partial_{t}(u^{2} + v^{2} + w^{2}) = 0,

where u, v and w are functions of x and t and the initial conditions u=v=0, w=-1. Then how to plot this equation on maple?

Dear all

I applied the definition of a permutation matrix to a given matrix A to obtain a Tridiagonal Toeplitz matrix, but I haven't any idea why the final result looks strange.

Permutation_matrix.mw

Many thanks

Dear all

Using maple I can't obtain an exact solution, my goal for which initial condition can the solution diverge to infinity if maple can not give us a solution.

special_condition_diverge.mw

many thanks

Dear all

I would like to compute a Laurent of a given function at an isolated point.

laurent_series.mw

thanks for your help

Dear all

I would like to solve a linear system A X=b whee A is a matrix n times n

If A is a tri-diagonal matrix, how can we write simple code to make A upper-triangular and then we solve the system using backward substitution

many thanks

I am trying to simplify an expression, and leave W in terms of other variables. But unfortunately I can't delete the RootOf, and I can't see the expressions. Could you please help me.

Dear all

I have an optimization problem. I would like to add a condition to obtain only a positive integer as the solution to the problem 

Positive_integer.mw

thanks

Download AB.mw

Dear all

I hope to find the maximum of a given function or show that the maximum is negative.

negative_maximum.mw

many thanks for your help