Oliver K

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16 years, 323 days

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These are answers submitted by Oliver K

In document mode, you can switch to nonexecutable math by pressing function key F5 (cylces through math->text->nonexecutable math). This should let you prettyprint your line without evaluation.

The expand command also offers an option to avoid the expansion of subexpressions.





Another way

eq1 := [diff(kk(r), r) = 0, ff(r)*1/2 = 0];



If you expect 1+y'=0 as result, you have to explicitly describe y as dependent on x:



By the way 1=0! is correct :o)

Well I'm not a developer, I can only speculate. Maybe it is because the falling bar in MapleSim  has its masses concentrated at its ends and the simulink model assumes otherwise.

Do you have a barbell in reach, so that you could perform some falling experiments?



I think one has to find the proper values for damping and the elastic constant. Also, I added a horizontal reactive force to the ground of 2.msim, as you can see in the custom component. Show you roll of wrapping paper model.




here an example how to model the falling rod. It can be easily extended to more complex examples in 3D, like cube, pyramid or something, just add some more mass points with their own attached subsystem, which checks if the position of the rigid body component drops below ground and applies an reactive force to it, if required.



Here the model of a rolling dice:


How about this? There is a signal force step in this model that works on a prismatic. After 2 seconds, the force goes to zero, and the "rope" is released.




Your worksheet opens fine here (Maple 16.02). There is a recursive assignment error in there, but all is readable.
Maybe a cold start would just do the trick.



y:= A*exp(-beta*(x-L-c*t)^2/(L^2));



Use Strg+J to insert a new execution group after cursor (Strg+K before cursor). Just type ?shortcuts to get an overview and select the help page you want from the list.

overview of packages: ?index,package

example to check content: with(LinearAlgebra);

you can ask for specific help pages to a command by entering it with a leading question mark, like ?inifcns

In case you don't want or can't solve the DE explicitly, use DEplot:

DETools[DEplot]( diff(y(t),t)=k*(1-y(t)/M)*y(t), y(t), t=0..20, [y(0)=1] );

There are surely different ways to do this. start with creating the sequence. My starting point: 7/9 =0.777...
Then multiply that with 10^n and cut off the decimal places.

A:=proc(n) local m; convert([seq(floor(7/9*10^m),m=1..n)],`+`);  end proc;


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