## Using wsolve and package charsests for proving geo...

I would like to use method wsolve for solving polynomial equations. The method has been implemented by Wang: https://link.springer.com/chapter/10.1007/978-3-7091-6604-8_9

As it is written in the text the metod is part of charsets package. But I can seem to find it and active it. I can find package online (http://wang.cc4cm.org/charsets.html), but I don't know how to add it to Maple.

I need to use this method in order to prove geometry theorems (and not any other method will do) and compare my results with results of other researchers.

## how can found points on boundary line of surface...

dear all,

I have a problem when I try to find points on boundary of the surface.

the surface ploted from a matrix as follow:

Thanks

## How can plot3d a sub-surface from surface ?...

Hi, everybody.

I have a problem when I try to plot3d a sub-surface from a surface as follows:

 >
 (1)
 >
 (2)
 >
 > p:= proc(u,v) if u
 > h:= proc(u) 2*u  end proc:
 >
 >

sub-surface.mw

Thanks and have a nice day.

## Weibull Distribution Formula...

What is the Maple Formula for the Excel function: =WEIBULL.DIST(A1,2,6.2,FALSE)

where A1..A26 is 0..26  ?  How do I plot it?

Thank you, Les

## Vectors.Aproximate constants a,b,c....

So, i have 3 vectors:

A=2i-3j+ak

B=bi+j-4k

C=3i+cj+2k

where a,b,c are constants.

such that A is perpedicular on B and C, and the scalar product B*C=2.I have to estimate this constants using an iterative algorithm on Maple and then solve the problem using predefined function from Maple and compare the results.If you have an idea pls let me know.Thank you.Sry if I wasn't clear.

Ok, so i have this functions

where f(x) represent urban population and g(x) represent the rural population.

And i have to implement an algortihm in Maple to find out after what period of time x the rural population will be with 20% bigger than urban population.

I'm new in Maple and is a little bit hard for me to implement algorithms in this program.If you can help me with any idea, i will really apreciate.Thank you :).

## Finding and printing the sequence of prime number...

Is there a built-in function in Maple 2015 that identifies and prints prime numbers in a specified integer range?

## how to solve a system of trigonometric equations i...

Hi everybody,

I'm kind of new to Maple and i'm trying to solve a system of trigonometric equations inequality as follow:

f:= {((2*a*sin(S)*cos(S)^(2)))/(1-sin(S)^(3))<1,90> S>-90,a>1};

solve(f,{a,S});
Error, (in PiecewiseTools:-Convert) unable to convert

How can I solve the system?

Thanks a lot.

## Remove quote symbols when printing string to file...

I have a code that outputs a long string of mathematics after various string replacements which I save into a file in the format of a Python function. Here is the code (for a 1 x 1 matrix):

```restart:
Size:=1:
## This is the matrix which is generated in a string format
mat1:="Matrix(1, 1, [[-1/2*(A^8*hh*m3+6*A^7*B*hh*m3-2*A^7*hh*m3*z3+16*A^6*B^2*hh*m3-14*A^6*B]])":
## Open up file
filename2:=fopen(cat("Matrix", Size, "x", Size,"HH.py"),WRITE,TEXT):

## Format file
fprintf(filename2,"import numpy as np\ndef myfuncHH(A,B):\n    z3 = 2\n    m3 = float('inf')\n    Mat_size = %a", Size):
fprintf(filename2,"\n    arr = np.array([%a",mat1):
fprintf(filename2,"],dtype=np.float64)"):
fprintf(filename2,"\n    shape = ( Mat_size, Mat_size )\n    HH=arr.reshape( shape )\n    return HH"):
fclose(filename2):
```

This generates almost the exact output that is required:

```import numpy as np
def myfuncHH(A,B):
z3 = 2
m3 = float('inf')
Mat_size = 1
arr = np.array(["Matrix(1, 1, [[-1/2*(A^8*hh*m3+6*A^7*B*hh*m3-2*A^7*hh*m3*z3+16*A^6*B^2*hh*m3-14*A^6*B]])"],dtype=np.float64)
shape = ( Mat_size, Mat_size )
HH=arr.reshape( shape )
return HH```

The part I want to remove is the "Matrix(1, 1, [   "Maths in here"   ])"]

I can use stringtools to tidy up most of this, but I am having trouble getting rid of the quotes of the string itself. I have tried escaping them and that does nothing. Is there a simple way to do this or will a regex have to be made?

- Yeti

## Transform arbitrary ODE system into first order fo...

Imagine we have an ODE system

odeSys := {diff(x(t),t\$2)+diff(x(t),t)+x(t)=f(t),diff(y(t),t\$2)+2*diff(y(t),t)+3*y(t)=g(t)};

It is easy to transform this system into a first order form by hand. But for larger systems, the procedure by hand becomes very error prone. Is there an intelligent way to transform a system of n scalar ODEs (order m) into a first order system? I know that the first order form is not unique. It is only important to reduce the system to a system of first order equations.

## Integral of complex function ...

I need to calculate the following complex integral:

oint_C { [(z^4exp(2z)+1)/(z+i)^3] - [(z^3+z)/{(z-2i)(z-5)}] + 8*Pi*exp } dz,

Where C is the circumference |z-1| = sqrt(11/2), positively oriented.

Someone can help me, I already researched but I can not integrate.

## In evaluating an integral Maple outputs a function...

What is the Phi function.  And more importantly how do I find out in general waht a symbol represents.  I input Phi in help menu, nothing useful comes up.  I use Function advisor, don't see a Phi symbol or anything beginning with Phi.  Isn't there a way I can select the symbol in the output and get help on it by pressing a F key?

Ok so I try FunctionAdvisor(describe Phi) - it gives me general Lerch Phi function.  But when I go to help page on LerchPhi, nowhere does it use Greek letter Phi to describe the function.  So I finally figured it out as I was composing this question.  But in why does the help page not use the symbol for the function that is displayed in the worksheet?

## System of partial differential equations with boun...

Hello,

I am trying to solve analytically a simple system of partial differential equations with boundary conditions and I am not able to do it. Even in the very simple case of

pdsolve([diff(u(x, y, t), y, y) = 0, diff(p(x, y, t), y) = 0, u(x, 0, t) = 1, (D[2](u))(x, 1, t) = 0, p(x, 1, t) = 2], [p(x, y, t), u(x, y, t)]);

I don't get any answer.  However if I remove the boundary conditions I get the right answer

pdsolve([diff(u(x, y, t), y, y) = 0, diff(p(x, y, t), y) = 0], [{p(x, y, t), u(x, y, t)}]);
{p(x, y, t) = _F3(x, t), u(x, y, t) = _F1(x, t) y + _F2(x, t)}

Can maple 2015 solve analytically systems of partial differential equations with boundary conditions? I have not been able to find any example anywhere.

Thanks a lot for your help.

Javier

## Error, unable to parse ('local' command)...

Hi, i'm working with some spectral acceleration data and i'm having troubles with a 'local' command on a Newmark method code i found on the internet. I'm not a maple expert so i wish someone could help me. i'm ussing maple 2015. Greetings

Newmark=proc(z0,u0,F0);  local beta,  dt, c, kg,a,b, N, i, dF, dz, du, dw, T, m, k ;        dt:=0.01;    T:=4;    N:=T/(dt);    gam:=0.5;    beta:=0.25;      m:=0.320;    k:=435;    c:=2;   z(0):=z0;   u(0):=u0;   F(0):=F0;   w(0):=(1/(m))*(F0-k*z0-c*u0);        t=vector(i,1);    t[1,1]=0;      for i from 2 to N do :  t(i,1)=t(i-1,1)+dt:  end do:           kg:=k+(gam*c)/(beta*dt)+m/(beta*dt*dt);    a:=m/(beta*dt)+(gam*c)/(beta);    b:=  (0.5*m)/(beta)+dt*((0.5*gam)/(beta)-1)*c;       for i from 2 to N do  dF(i):=diff(F,t)+a*u(i)+b*w(i);    dz(i):=(dF(i))/(kg);    du(i):=((gam*dz(i))/(beta*dt))-((gam*u(i-1))/(beta))+dt*(1-gam/(2*beta))*w(i-1);    dw(i):=((du(i))/(beta*dt*dt))-((u(i-1))/(beta*dt))-((w(i-1))/(2*beta));     z(i+1)=dz(i)+z(i);    u(i+1):=du(i)+u(i);    w(i+1):=dw(i)+w(i);     od;       plot([z(i), u(i), w(i)],x=0..50,y=-50..50);       end;

## AFactor doesn't factor a (supposedly) reducible po...

```with(algcurves):