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I got a problem with a difficult ode,the commands are below.

restart;
sys := 1.*(diff(x(t), t, t)) = piecewise(b(t) = 1, 0, 1003.0-1000.*x(t)-30.*(diff(x(t), t))-25.*signum(diff(x(t), t)-.1)-.3*signum(diff(x(t), t))*exp(-2*abs(diff(x(t), t)))), x(0) = 1, (D(x))(0) = 0;
mu := 100;
stick := [diff(x(t), t) = .1, b(t) = piecewise((1000.-1000.*x(t))^2 < 10000, 1, 0)];
slip := [[0, 10000 < (1000.-1000.*x(t))^2], b(t) = 0];
sol:=dsolve({sys,b(0)=0},numeric,discrete_variables=[b(t)::float],events=[stick,slip],event_maxiter=1000000,output=listprocedure,maxfun=0,range=0..8);

any advice is appreciated.

Hi Everybody,

I'm having some problems simulating an algebraic system in Maple.  I want to do this for a larger system of equation (~20 equations/20 variables, with 3 inputs), but I'd like to get an idea of the form this should be in.

So, using an example out of Maple help:

with(DynamicSystems);

sys1:=AlgEquation([y=sin(x)],[x],[y],discrete=true,sampletime=0.001);

inp1:=Vector[column]([1,2,3,4,5,6,7]) * 0.1;

res:=Simulate(sys1,[inp1]);

Error, (in DynamicSystems:-Simulate) should never be here

 

I don't understand what this error means.  Reading the example in the help files, says the second argument should be a vector of input values.  What I would assume this would do is plugin x = 0.1, then solve y=sin(0.1), and output y.

Am I missing some syntax, or is my inputs wrong?  There are examples of how to set up an algebraic system in the help files, but no examples of how to simulate them.

 

Thanks in advance for any help!

 

 

 

 

Hello, I am trying to do a fourier transfrom using the package < DiscreteTransfroms >.

The function is an gaussian function for now,

Here is the code I tried

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

restart

with(DiscreteTransform):

> X := Vector(1000, proc (k) options operator, arrow; (1/200)*k-5/2 end proc);
> Y := Vector(1000, proc (k) options operator, arrow; evalf(exp(-10*((1/100)*k-5)^2)) end proc);

> X2, Y2 := FourierTransform(X, Y);
Vector[column](%id = 18446744080244879358),

Vector[column](%id = 18446744080244879478)
> plot(X2, Re(Y2));

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

The program returns two vector, X2 and Y2 who are supposed to be the fourier transforme of a gaussian so.. a gausian but when I plot the result X2 on the horizontal and Y2 on vertical, the graph doesn't resemble a gaussian function or any function at all.

 

Please help!!

Alex

Let's say we have the response of a discrete system  to a unit step, the measured data is available as a vector in Maple. As example: seq(evalf[2](exp(-n/5)*sin(n)),n=0..20);

How can I find the coefficients of the transfer function G(z)=(a1*z+a2)/(b1*z^2+b2*z+b3)?

Here is a paper that describes on page 27ff how to do this with regression.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.136.373&rep=rep1&type=pdf

Maybe there is a better way.

Hi, 

I am relatively new to Maple and I am seeking an efficient way to create a probability histogram for a discrete probability distribution. For example,

x:      1     3   5    7

p(x): 1/8 1/4 1/2 1/8

 

I would like rectangles with height corresponding to the probabilities with bases centered at each x value, allowing for the possibility of gaps in the distribtuion.

 

 

I have a sample waveform of an air conditioner and want to see if any low frequencies (10 Hz which is harmful to human health) exist in the wave.  How can I do that?

 

Granted the frequencies picked up in the recorded file depend on the quality of the recording and the recorder and lower frequencies may not have been picked up. 

 

I've looked at

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