## Solving a kinematics problem...

Hi, I want to solve a kinematics problem. I have the following DE: > eq1:=diff(v(t),t)+4.646e-4*v(t)^3-7.13e-3*v(t)^2-0.085*v(t)-2.82: Where v=v(t) is the speed and t the time. My goal is to get the space crossed in a period of time: from t=3.35 to t=4.77 (seconds). Additional info: v(3.35)=14.77 m/s v(4.77)=20.4 m/s I've tried solving this with Maple but I couldn't (I'm a Maple newbie). This is what I tried: 1) I isolate the v and dv terms equation, so that: dt=dv/(-4.646e-4*v^3+7.13e-3*v^2+0.085*v+2.82) 2) Then I integrate that to get the time is function of the speed, t=f(v).

## Maple in education?...

Is there an online forum/discussion board devoted to the use of Maple in mathematics education? The forums I know about (here, usenet groups), seem mostly technical. But I have some education questions I'd like to ask - I just don't know where to ask them. cheers, Alasdair

## Optimizing...

I am trying to optimize a function using NLPSolve. The function is in Matlab and Maple calls the function and optimizes it. The values that I am getting are not correct. The optimal values of the parameters are outside the range tha I specify and the function value is not what should correspond to these optimal values. I have attached both the Maple and Matlab codes herewith. Looking forward to your help. Maple File: restart; Matlab:-evalM("cd 'c:/documents and settings/user/my documents'"); mat2map5 := proc (a, b) local Res, res; Matlab:-setvar("a", a); Matlab:-setvar("b", b);

## Calling Matlab from Maple...

I am trying to call a Matlab function from Maple code. In doing this I am facing the following proble: When I use this statement to identify the matlab directory I get an error messgae "too many input arguments": (Matlab:-evalM)("cd c:/documents and settings/user/my documents") However, it works when I use the following: (Matlab:-evalM)("cd c:/") I would highly appreciate if someone could help me out with this. Thanks

## Where is the problem? Why I cannot pointplot3d?...

Hi Maple's experts: (I am using Maple 10.01+WindowsXP ) Given 2 set of numbers x=[1,2,3] and y=[1,2,3] I generate a third which is the addition of x[i]+y[j], as follows: > restart: > with(ArrayTools): > x:= Array([1,2,3]); > y:= Array([1,2,3]); > zxy:=NULL: > for i from 1 to 3 do for j from 1 to 3 do zxy:= Concatenate(1,zxy,Concatenate(3,Array(x[i]+y[j]),Array(x[i]),Array(y[j]))): end do end do: > print(zxy); #I cannot see the "data" > print(zxy[3]); # I see the third line > with(plots): > pointplot3d[{zxy}]; #I cannot plot HERE..."zxy" contains what I want.

## open and close...

I am a beginner with Maple and want to translate a code, that I wrote in Matlab, to Maple. I am facing very basic problems like how to open a data file, how to manipulate data and to write the results in another data file. I would highly appreciate if someone could send me a sample code that performs these very simple tasks. Thanks

## Hide output in for loop...

Stupid question maybe, but how can you hide output of a for loop? The usual : does not work here... Thanks for your help.

## Maximization of x1+x2+...+xn...

Imagine you have to solve the following problem. xi*(a-(x1+x2+...+xi+...+xn)-b) However, we can not see ex ante that all the x's are the same. So, I would like to differentiate to xi and equal the derivative to zero. So, I should have xi in function of the other x's. I hope anyone can see what I mean and I beg you to answer me because this is very important for me. Thanks a lot. Greets Jan

Hello, suppose you have the following function which gives 1 if both its arguments are even: G := (i,j) -> if is(i,even) and is(j,even) then 1; else 0; end if; Then what is the difference between these two statements: sum( sum( G(i,j), i=0..5 ), j=0..5 ); add( add( G(i,j), i=0..5 ), j=0..5 ); The first one gives 0 and no sum is actually computed (you can see this by adding print(i) and print(j) statements in the body of G). The second one gives the correct result, namely 9. How come i is not replaced in sum? -- Thanks for any reply, Franky.

## plotting multiple 3d data sets on a single plot...

How do i plot a bunch of 3D data sets. If it were just one set i could use pointplot3d i suppose. with(plots): > l1 := [[1,2,2],[3,4,2],[1,5,6],[7,8,9]]; > l2 := [[1,2,2.5],[3,4,2],[1,5,6],[7,8,9]]; > plots[pointplot3d]([l1,l2], axes=boxed, labels=[x, y, z], > connect=true); #DOESNT WORK More exactly i want to plot the data sets (11 rows each) pasted below. 1.000000000000 1.000000000000 .571428571400 2.000000000000 1.000000000000 .139941691000 3.000000000000 1.000000000000 .068542869040 4.000000000000 1.000000000000 .041965021860 5.000000000000 1.000000000000 .028776014990

## Embedding Information...

I was wondering if anyone was familiar with an easy way to embed or hide information into a Maple worksheet (Classic worksheet or Maple 9/9.5 standard worksheet, NOT a Maple 10 standard worksheet)? I want to be able to be able to have something equivalent to a checksum. We are producing Maple worksheets as homework for students, and I want to have something that the sudent cannot easily change to make sure that he or she is not submitting a friend's homework.

## Very good books of Maple.. which ones?...

Hello, I want to learn how to program with Maple..Could someone - please- suggest a couple of very goods (..if they exist) for that purpose?. Regards, Jean Jacques.

## Graphing differential equation...

Hey guys, I'm having a bit of trouble graphing the following: f'''(x) + f(x)*f''(x) = 0 where f(0)=f'(0)=0 and f'(infinity)=1 My specific problem is that I can't set f'(0)=0 and f'(infinity)=1 thanks, Rebecca

I am trying to solve (numerically) the following system of differential equations using dsolve (Maple 9): DGLS:=seq(seq(diff(B[i,k](t),t)=add(add(W(j,l,i,k)*B[j,l](t)-W(i,k,j,l)*B[i,k](t),l=1..N),j=1..N),k=1..N),i=1..N); The problem is posed by the coefficients W(i,k,j,l). I want to make the W(i,j,k,l) dependent on the unknown functions B[i,k](t). For that purpose I wrote a Maple program W := proc(i::integer, k::integer, j::integer, l::integer) which calculates a "transition probability" Wtrans. If Wtrans does not depend on the B[j,l] (e.g. Wtrans:=1/N^2;), everything works nice. However, if I try to use the B[i,k] somehow (e.g. if NKrit_jl > B[j,l] then Wtrans := 0.5 fi;), then error messages from the procedure W result like "Error, invalid terms in product".

## Extracting an integer coefficient from a term...

```icoeff := proc(t)