Hi , 

 u(t-n*Pi)=0 if (t-n*Pi)<0

 u(t-n*Pi)=1 if (t-n*Pi)>=0

need to plot y(t) against t where t=0..30:

y(t)=sum(sin(t-n*Pi)u(t-n*Pi),n..infinity)

I appreciate 

How should I save my result-expression so as to be able to use it directly in other file without having to generate it again.

please help
regards,

Hi,

My work requires me to use derivative a lot. Especially, the partial one. Given F(x,x_dot). Maple has this partial expression, however I'd like to partial differentiate F with regard to x_dot (the derivative of x over time).

Is this possible? If possible, please tell me how.

Thank you.

Abe

i had a 15 set of nonlinear PDEs,i convert them to nonlinear set of ODEs, i try to solve them using the command dsolve(numeric) , but when solving i face this erroe :

Error, (in DEtools/convertsys) numeric exception: division by zero

what should i do?the problem is in my equations ? or what?

with regards,thnx. 

Hello, 

I'm importing some other modelica models from other softwares (like open-modelica and dymola) inside maplesim. I can work in a full compatible code, except for the lookup table. Some of the models I'm importing as a library uses the standard lookup tables (not the ones given by maplesim) - I tried to run those standard lookup tables (from the modelica library) in maplesim, but it does not work.

Is there a way to solve...

A wonderful plot I have found created by Matthius Kawski in Maple 8.  But newer versions creates an Error, (in f) unsupported type `complex(float)` in evalhf in the DEplot.  Can someone fix the error?  Worksheet is attached.

lyap-not-proper.mws

I have this csv file on my website (the file is hosted on dropbox.com) that I want to load into Maple:
Hence I type:

URL := "https://dl.dropboxusercontent.com/s/7fqalrdtn0c3r8u/Stockholm%20Stock%20Exchange%28Percentage%20Change%29.csv?token_hash=AAGxpzva90O6oNlLAie3T1h0UNP06I5EPg2qrROHMglRMw&dl=1":
HTTP:-Get(URL, 'timeout' = 100)

Then I get:

Error, (in HTTP:-Get) timed out waiting for initial response from server

If you past the url into...

Here is a relation: t[n+1]:=((a*n^2+a*n+b)*t[n]+c*(n^2)*t[n-1])/(n+1)^2

t[-1]:=0 and t[0]:=1

a,b,c are integers and a,b,c are from 1 to 20 and n is from 0 to 20

the series t[n+1] is integer

I want to know how to list (a,b,c) that satisfies the above. Please help!

I was using the Finance package and used the command ImpliedVolatilitySurface(...). But it is showing the following error 
"Error, (in Finance:-ImpliedVolatilitySurface) external linking: error loading external library finance.dll: The specified module could not be found."Please help..

After solving a system of differential equations I got module. So I have a solution for the functions U1 (x, t) and U2 (x, t). Please tell me, how do I now get x * which corresponds to U1 (x *, 10) = max?Help please.

Hi,

I have to get the numerical solution of a systems of differential equations, but with the particularity of that one of its equations contain an integral. I mean, something like this:

"bc1"...

Hi,

I need help about this equation.

In geometry (2D), the triangle ABC has centroid is G(1, 1) and orthocenter is H(1,1). How to find the vertices A, B, C with the coordinates of this vertices are integers number?

Why is there a difference between pdetest and algsubs for a PDE?
Shouldn't pdetest work the same as algsubs for the example below?

restart: with(PDEtools):

Eq:=u(x,t)*diff(u(x,t),t)=0:

tmp:=sin(w*(c*t-x))-(1/4)*epsilon*c^2*cos(w*(c*t+x))^2+epsilon*c^3*w*cos(w*(c*t-x))*sin(w*(c*t-x))*t+(1/4)*epsilon*c^2*cos(w*(c*t-x))^2+(1/8)*c^4*epsilon^2*sin(w*c*t+w*x)+(1/8)*c^4*epsilon^2*sin(w*c*t+w*x)+(1/24)*c^4*epsilon^2*sin(3*w*c*t+3*w*x):

sol:=u(x,t)=tmp:

> restart; R := 8.314; printlevel := 2;print(??); # input placeholder> G1[1] := piecewise(`and`(T > 298, T < 700), -7976.15+137.093038*T-24.3671976*T*log(T)-0.1884662e-2*T^2-0.877664e-6*T^3+74092/T, `and`(T >= 700, T < 933), -11276.24+223.048446*T-38.5844296*T*log(T)+0.18531982e-1*T^2-0.5764227e-5*T^3+74092/T, `and`(T >= 933, T < 2900), -11278.361+188.684136*T-31.748192*T*log(T)-0.1230622e29/T^9, 0);print(??); # input placeholder

> G1[2] := piecewise...