I was wondering if someone can help me solve a problem of kirchoff's law using maple, heres the problem:

Use maple and Laplace transform to find the charge q(t) on the capacitor in an RC series circuit with the following conditions; graph q(t) on the interval 0<t<6 and use the graph to estimate the time and value of the maximum charge

q(0)=0

R=50 ohms

C=.01 farads

E is a piecewise where 1<x<3 = 100, everywhere else is zero

I'm assuming that since nothing is said about the inductance in the initial conditions, L=0

heres what i got so far:

>i(t):= diff(q(t),t);

>KirchoffLaw:=E[R]+E[L]+E[C]-E[emf]=0;

Consider the following three problems:
1) given a list [a,b,c,d,e], return the list [a=1,b=2,c=3,d=4,e=5]
2) given a nested list [a, [b, [c, [d, [e]]]]] return the list [a,b,c,d,e]
3) given an integer in base 10, compute it's base b representation
First I will show you what not to do:

L := [a,b,c,d,e];
M := [];
for i from 1 to nops(L) do
M := [op(M), L[i]=i];
end do;

Building up lists (and sets) incrementally is quadratic time, because each iteration of the loop allocates linear storage to hold the new list. The standard solution is a loop with a temporary variable, assigning to a table:

April 11 2006
JanE 28
The following interactive worksheet gives you the possibility to plot functions in 2D and 3D. There is also an interactive version available on the MapleNET - Server. You find it here. You can also download the worksheet here and run it in your Maple.

I will try to publish further versions with more possibilities to plot in the next weeks.

Ten days playing with Maple has proven that skills in one system don't necessarily translate to another. I have encountered a number of frustrations which are not so much a problem with Maple as my inability to match the subtleties of the new system. Some of the issues I have encountered:

- periodic locking up of the interface in document mode (this may be due to something I am doing wrong)
- getting used to the maple syntax and command list (it is further than the syntax of Mathematica than I originally suspected yet similar enough to completely mess me up)
- occasional odd state like behavior (which is, again, probably due to my ignorance than a problem with Maple)

Hey all
I would like to know if after solving a Matrix Differntial Equation (general form, no initial conditions) there is a way to convert the solution matrix to equation form (i.e. y(t)= C_1e^(3t)+C_2e^(-t)+... etc).
see yas
david

I haven't been to mapleprimes for awhile and noticed that the "convert worksheet" option is no longer available. Are the "file manager" and "upload file" options very different from the previous worksheet converter, and are they also any more difficult ?

I'm working on some basic complex number equalities in engineering class, and was practicing converting from cartesian to polar coordinates. Maple can help by telling me if my conversions are correct by telling me whether the equality is true. For example, for the complex number: 5 + 3*I maple will verify the following:
is(5+3*I = polar(sqrt(5^2+3^2), arctan(3/5)))
true
it will also verify:
is(polar(sqrt(5^2+3^2), arctan(3/5)) = sqrt(5^2+3^2)*exp(I*arctan(3/5)))
true
lastly, it will of course verify transitively:
is(5+3*I = sqrt(5^2+3^2)*exp(I*arctan(3/5)))
true

I am struggling with the new LinearAlgebra package and I want a procedure for the vec operator (just stacking the colums of matrix r by c into a (r*c) by 1 columnvector. For only extracting two columns the following commands work well: A := Matrix(5, 5, symbol = a); Matrix([[Column(A, [1])], [Column(A, [1])]]); but there must be a simple procedure for doing this for a converting a large matrix into a column vector. Any help would be appreciated. kind regards, Harry Garst

I am converting a complex worksheet from linalg to LinearAlgebra, and
discovered what is to me a serious problem. With linalg, one could use
the basis(A,colspace) command to give a basis of the column space consisting of columns from the original matrix, guaranteed to be in the order in which they appear in the matrix. This is useful in extending a spanning set of a vector space to a basis of a larger space, and allows one to determine exactly which new vectors need to be added. However, the ColumnSpace(A) command in LinearAlgebra does something quite different. It gives a basis of the column space which does not preserve this order, and does not even use the original vectors.

One of the best features of MaplePrimes is that members can incorporate typeset 2-D mathematics into their posts—a huge advantage over text-only forums like Usenet, for example. MaplePrimes currently allows math input using either Maple syntax or MathML. There may be a straightforward way to support the input of 2-D math using TeX/LaTeX as well. This post suggests one possible way to add this new functionality to MaplePrimes.

Hello, all! I have a linear system of real numbers. I copied the example in the tutorial for using LinearSolve and converted my matrix to a float:
with(LinearAlgebra);
my_solve := proc(A::Matrix)
local sz, local_A, B, sol;
sz := Dimension(A);
local_A := Matrix(A, datatype=float);
B := Vector(1...sz[1], 1);
sol := LinearSolve(local_A, B);
end proc;
And when it solved, it got the wrong answer!! It would produce a solution that simply didn't work. When I removed the float conversion step, and just used my original matrix, it worked perfectly.
I would love to understand this better... is it because of rounding?

I've had considerable difficulty in integrating products of trig functions with Maple. It usually expands the trig functions into forms that just are a mess to deal with. So, I usually handle this by splitting an expression into two parts: a constant term that doesn't depend upon the integration variable and a dependent term. In the past, I've usually done this by hand but have now created a procedure to do this automatically.

February 09 2006
fawzi 8
I seems that CodeGeneration fortran uses internally lists that can get longer

than 100 elements converting complex procedures.

executing

"Fortran(long_procedure,defaulttype=float,optimize);"

I get the following error message

"Error, (in GetNameReplacementList) assigning to a long list, please use

Arrays"

9.5 handled this without problems.

I join a worksheet that (as very last command) shows the problem.

I reported already this problem to the technical support, but now I post it also here.

Fawzi

February 04 2006
rellik 8
I am trying to multiply a number in volts with a number in mV. the answer it gives me, though, is in [[V]]*[[mV]]. How do I make it convert the answer to [[V]] automatically?

Hi, I just bought Maple, and I'm really excited about it. I'm poking around in Maple, trying to get comfortable with it, by entering in a problem from my physics class. In this class, we use SI units, except that we express our angles in degrees.
I'm trying to find an easy way to have the trigonometric functions take degree arguments. I tried "with(Units); with(Units[Natural])", and entered an expression this way: "R_x = R*sin(15*deg)", and that almost worked. There were two problems, though:
1. R is apparently a unit in its own right...not *too* much of a problem (I can choose another letter), but annoying.