I was solving thos differential equiation using dsolve:

diff(P(t),t)=b*P(t)+m*t

dsolve({diff(P(t),t)=b*P(t)+m*t,P(t0)=P0});

where t0=2000 and P0=100 and m=9/50

Then, I found b setting at t=2001, P=2*P0=200, I applied fsolve to do this and the result was:

b=-1.5979...

To this point, Maple computes correctly. The problem starts when I tried to plot the result in a single 2D-graph (P vs t) using the computed value for b, the expression involved is:

P(t)=.1126460951*t-0.7049523744e-1-1.090463096*10^1390*exp(-1.597924898*t)

I wrote

plot( .1126460951*t-0.7049523744e-1-1.090463096*10^1390*exp(-1.597924898*t) , t=2000..2001);

The result was a blank plot, only the axes appeared even if I used the y=A..B option in the plot command. Is there a way to get the desired plot without having to evaluate the function at several points and then using this set of points to generate the plot: plot({[a,b],[c,d],[f,g]...})? (that worked, of course).

Thanks and regards.

P.S. I have used Maple for over 15 years now and I've plotted expressions even more complicated than this one, I found this very strange. I guess the 10^1390 has something to do this time, but I'm not sure...

I would like to import the code from Pg 90 on in the following document into Maple. Any suggestions for doing so with minimal editing required after pasting? http://mspace.lib.umanitoba.ca/xmlui/bitstream/handle/1993/14907/Huang_Liji.pdf?sequence=1&isAllowed=y

thanks,

I have an arrays of data. One for x values, and one for y values. How can I obtain a numerical integration of y for a range of x values?

I have tried defining a function of X using ArrayInterpolation(x,y,X) and then calling evalf(Int(f,xmin..xmax)) but that gives an error message. (I don't seem to be able to paste into this window) The error message says

"Error, invalid input: evalf expects its 2nd argument, n, to be of type posint, but received numeric."

I thought I was using a form of the equation right from the help system.

I also tried the 2D version of integration, but it returns the difference of my limits times my function name.

I aslo tried AdaptiveQuadrature, but I can't get that to work either.

-Mike McDermott

Newbie Maple user

by_parts.mwhi, plz someone tell me what I have to do for such type of error

i posted these ealier without any responds,pls i need some assistance my project supervisor has made it mandatory that i build a maple maplet of the bessel equation:

  i would have loved my maplet to have four knobs/sliders to vary the value of the parameters(T[g],T[0],k,p)  and also a play puase and stop bottons while texts boxes to type in the value of the unvaried parameters(gamma,G,alpha,delta,C[1],C[2]) and this maplet should show a 3d and 2d plot of the equation of which the various varying parameters can be varied to see effect on the plots.1.e 3d plots of (F against p and T[o]),(F against k and T[o]),(F against tortuosity and T[o]) which can be assigned to three different plot bottons but to be ploted on the same plotter and 2d plots of (F against p) and (F against k), (F against tortuosity) which can also be assigned to three different plot bottons but to be plotted on a second plotter aside that of the 3d plots.
i will really gratefull if anyone can help me out,thanks in advance<

Hi,
I'm new at maple and have a problem/question with the rkf45 numerical ODE Solver.

At first, my computer need a lot of time to calculate an analytic solution.
Therefor, I use the numerical way.

I have the following second order ODE:
ODE:=m*((D@@2)(x))(t)+d*(D(x))(t)+k*x(t) = d*(eval(diff(y(x), x), x = t))+k*y(t)
where y(t) is a realy big piecewise function, defined by me.

My initial conditions are:
x(0) = 0, (D(x))(0) = 0

With dsolve, I get the solution x(t) and the first derivative x'(t). I'm able to plot them with odeplot.

But...

Problem 1:
I need also the second derivative x''(t).
On this page: http://www.maplesoft.com/support/help/maple/view.aspx?path=dsolve%2Frkf45there is an example (eq 13 and 14) where the second derivative is useable, but this doesn't work with my differential equation.
I have add 
(D(D(x)))(0) = 0
to my initial conditions but then, I got the error that only 2 initial conditions are required.
What could I do, so that rkf45 returns also the second derivative?

Problem 2:
And in addition to this, I want to calculate with x(t), x'(t), x''(t) but I found no way to use them.
Only plots are possible.
If I reduce y(t) to a minimum, I can do everything with the analytic solution: plot, d/dt, d2/dt2, +, -, ...
I tried also to convert the procedure to a function but in this case, there is no way to derivate it.

Many thanks...

https://drive.google.com/file/d/0Bxs_ao6uuBDUVkE1b2pmcnljcnc/view?usp=sharing
https://drive.google.com/file/d/0Bxs_ao6uuBDUbE56R3Z1c0tLRkE/view?usp=sharing

restart;
changering := proc(Equation1, f3,g3)
g1 := (x,y)-> f3;
f1 := (x,y)-> g3;
h:=subs(g=g1, Equation1);
h:=subs(f=f1, h);
h:=subs(0=0, h);
return h;
end proc:
Eq1 := f(x,g(x,y)) + f(x,y);
h2 := changering(Eq1,x+y, x+y);
h2;

g1 := (x,y)-> x+y;
f1 := (x,y)-> x+y;
h:=subs(g=g1, Eq1);
h:=subs(f=f1, h);
h:=subs(0=0, h);

Dear All

I am trying to integrate a function, however Maple is not giving me the results. I have tried to use int as well as evalf however I am still not getting the results.

I would be grateful if you could please suggest me a way out. I have attached the maple file for your reference.

ThanksExample.mw

I have this data I want to import in to Maple.




In Maple I type:

ImportMatrix("C:\\Users\\marc\\Desktop\\data1.csv", delimiter = ",");

then I get the following:




My question now becomes how can I import the data with the correct dates and not just -Aug, 1-Aug etc ?
The method should also work when I have many more columns of dates.

Ps I cant upload the data on MaplePrimes since it is a csv file.

how to show chain rules result when diff this

Eq1 := f(x,g(x,t)) + f(x,y);
diff(Eq1, x);

 http://math.stackexchange.com/questions/372093/chain-rule-definition-f-fx-gx-y

https://drive.google.com/file/d/0Bxs_ao6uuBDUanVWYm1SMWc4R3M/view?usp=sharing

Hello All,

I have the PDE system shown below. It is a simple system for 2 unknown functions f1(x,t) and f2(x,t). Also, say we have x=x(t)=e^t for example. How does one solve such PDE system with Maple? I tried including the condition x=e^t in the PDE system itself, but got "System inconsistent" error message. x=x(t) can be looked at as an additional constraint and I am baffled how do I feed it into the PDE solver. 

Perhaps someone has experience with such systems?

Hi,

  My question is related to this one http://www.mapleprimes.com/questions/37447-How-Can-I-Sort-A-List-Of-List-According

but not exactly the same.

  Suppose I have lists

***

f[1]:=[1,3,2];
f[2]:=[2,1,3];
f[3]:=[1,2,3];
f[4]:=[2,3,1];
f[5]:=[3,2,1];
f[6]:=[3,1,2];

***

  The aim of sorting is first, arrange by ascending order of the first variable, then the second, then the third.

I could program manually by explicitly comparision, is there any robust way in maple can do it (possibly a few build-in function)?

Thank you very much!

Just trying Maple again after 10+ years, so please bear with me. I am basically trying to do a symbolic integration, where the output should be the antiderivative of the function I am integrating. However, I have not been able to succesfully get the output I expect.

I defined a function C_p(T), with constants C₁, C₂, etc. like so:

C__p := T -> C__1+C__2(C__3/(T*sinh(C__3/T)))^2+C__4(C__5/(T*cosh(C__5/T)))^2 

But when I integrate the function using int(C_p(T), T=T_ref..T_sys) it does not output the antiderivative as I would expect. This is what I am looking for, but it just gives me the equation within the integral sign without symbolically solving integral. Can this be done?

It should be,

int(C_p(T), T=T_ref..T_sys) = C₁*(T₂-T₁) + C₂*C₃[coth(C₃/T₂) - coth(C₃/T₁)] - C₄*C₅[tanh(C₅/T₂)-tanh(C₅/T₁)]

Trivial integrals such as int(x2,x) = 2x solve okay, so I am assuming I setup the problem incorrectly. I just cannot figure out what I did wrong, and it is driving me crazy. I already wasted more time than is healthy on this. Any help would be greatly appreciated. Thanks.