## plot command not working the way I want...

Motion_of_a_Charged_.mw

Hi,

The procedure I uploaded, was originally written in C++. I made a text file and plot the file with C++ without any problem.

But in the maple version of the same program, when I use the command:

...

## Solving ODEs first order and second order...

Hello all,

I'm a new user, hopefully you can assist me as I have work on this problem for quite sometime, I keep getting error of Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system

I copy my work here. If anyone need the original worksheet I can send this immadiately. Please help and I would like to say Thank you.

R:= 8.31434;             ...

## Constraints using NLPSolve...

Hello all,

I'm working through an optimization problem, and I'm running into a problem adding constraints on the variables I am trying to optimize. I'll attempt to ask the question in a general sense, but if it's not clear, I'll be more specific.

I have a procedure called EIG that calculates the sum of the squared residuals of a model compared to experimental data by inputting 6 variables. I'm trying to minimize this function by using the Optimization...

## How do I solve these ODEs?...

So I've solved this system of ODEs already in a certain gauge where h[r](r) was set to zero, and my answer was consistent with a previously calculated solution, but now I'm trying to do it with a non-zero h[r](r).

The previous result Maple easily solved with dsolve, but puting that in this time, I get:

ode := [-1/2*(4*h[v](r)*r+4*h[r](r)*r-2*diff(h[v](r),\$(r,2))*r^3-2*h[2](r)*6-2*h[r](r)*6*r+diff(h[2](r),r)*6*r+4*h[2](r)-2*diff(h[2](r),r)*r)/r^3=0,

## How doi I insert a legend in a PieChart from the c...

Hi

I need to insert a legend in a Pie chart, but I want to do it from the command line:

> with(Statistics);
> T := [algodón = 26, lana = 5, tabaco = 7, fruta = 9, arroz = 13, té = 5, carne = 14, otros = 21];
> P := PieChart(T, sector = 0 .. 360, color = ["red", "Orange", "yellow", "green", "ForestGreen", "blue", "MediumPurple", "LightBlue"], captions = relative);
> plots[display](P, title = ["Distribución de las exportaciones...

## Switching Modes...

Is it possible to switch between worksheet mode and document mode? If yes, how?

## How can I solve these ODE's?...

Hi everyone;

I would like to solve these ODE's.

1) d/dX(X*dΘ/dX)+ρ^2*X*Θ=0;Θ=Θ(X),ρ=constant

2)d/dr(r*d/dr(φ)-m^2(r*φ-n/m^2)=0;φ=φ(r),m,n=constant

Boundry Conditions are:

1)d/dX(Θ(L))=0,  2)Θ(0)=φ(R), 3)d/dX (Θ(0))+d/dr(φ(R))=0, 4)d/dr(φ(0))=0,   R,L=constant

Two of boundry conditions are Joint

Thanks

## dsolve, events question...

My question is in regards to the events feature in dsolve numeric.

At a particular event time, I was wondering if it is possible to call a previous moment, that is something like

eq:={ diff(y(t),t) = y(t) };

ic:={ y(0) = 2 };

de:=dsolve( eq union ic, numeric, events=[[ t =5, [ y(t) = y( t - 2 ) ]]],range=0..10);

If it is possible to "globaly" declare previous steps of the dsolve, I believe that the above de would work. However,...

## Help with Simultaneous Equations...

Hello,

I have this relatively simple 4 equations which I am trying to solve simultaneously. But for some reason Maple just returns a pair of empty square brackets as solutions. "[ ]" like this.

I have uploaded the Maple Worksheet for your convenience. It would be very helpful if anyone can take a look at it and point out out the problem. Thank you.

Simultaneous_Eq.mw

## Saving dsolve numeric solution...

Hi, im Gabriel from chile, and probably my english wouldnt be very good :P.

Im working on a problem that needs to be solved numerically, its a set of coupled non linear equations. Im succefull in finding the solution given a set of initial conditions, but the problem I have is when I try to save those solutions.

I want to save them in a .m file to fully recover it when I start the session again (it take some time in find the solution, and I have to iterate the...

## Problem with graphics...

Hello, I need to know how to graph in Maple as follows:

the plane 2x + 3y - z = 5 and the cylinder x ^ 2 + 4y ^ 2 = 9 x ^ 2 + y ^ 2 = 1.

The idea is to plot everything in a single graph, as shown in the books of calculation.

I have tried in various ways, but I do not go away.

## Problem Evaluating Integral analytically ;...

I've been trying to evaluate another integral, like exp(-(alpha*x)^2) from 0, to infinity;

However it expresses the answer as a limit of some function(alpha), how do I get the integral to come out more exactly?

Thanks

## Numerical Integration...

Hello,
I have to find the internal of
E_field := conjugate((-.7147663039-.8729430992*I)*exp((9.123185068*I)*cos(phi))*cos(phi)+(0.3187576278e-1+0.3371906130e-1*I)*sin(phi)*exp((4.561592534*I)*(-1.*sin(phi)+cos(phi)))+(0.7062621752e-1+.1302618973*I)*cos(phi)*exp((2.000000000*10^(-11)*I)*(53.*cos(phi)+1.570796328*10^11))+(-0.3187599160e-1-0.3371906130e-1*I)*sin(phi)*exp((4.561592534*I)*(sin(phi)+cos(phi))))*sin(phi):

I try to solve by
evalf(simpson(E_field, phi = 0..2*Pi));

## fraction not canceling common Factors...

I was trying to evaluate a 2-dimensional integral, but my answer contained an expression like pi/pi^2;  even trying to simplify this did not reduce the fraction properly. Why does this happen, and how can I get it to display the answer properly?

Thanks

## how to fit data set to a pre-determined form of f...

I got two columns of data in excel: current (I) and voltage (V). What i want to do the following things:

1. read the data set into Maple 12.

2. plot the current vs voltage

3. Fit the plot to the function with polynomial form:  I=aV^2+bV

4. find the R-squared value of the fitted function.

Could anyone kindly tell me the detailed code to achieve this, thanks a million.

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