## 1201 Reputation

17 years, 238 days

## Make it Inert...

you could try an inert operator to get the desired form. use value() to enforce evaluations

restart;
with(LinearAlgebra):
b := Matrix(3, 6, [[-1/2, 0, 1/2, 0, 0, 0], [0, 0, 0, -1/2, 0, 1/2], [0, -1/2, -1/2, 1/2, 1/2, 0]]);

c:=`%*`(1/2,2*b);

c+3*c;

value(%);

## nonexecutable math mode...

Hi,
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.

## further options...

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

trigh-expansion.mw

## List Index...

Another way

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

eq1[1]

## Notation...

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

x+y(x)=1;

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

## don't know...

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?

:-)

## Damping...

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.

2.msim

## Falling rod...

Hi,
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.

1.msim

Here the model of a rolling dice:

## Prismatic and Force Component...

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.

Pendulum_with_Releas.msim

## Your worksheet opens fine here (Maple 16...

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.

## example...

restart:
f:=piecewise(x^2+y^2<3,y-x^2,undefined);
plots[implicitplot](f,x=-2..2,y=-2..2,scaling=constrained,view=[-2..2,-2..2]);

## Formal Power Series Option for Convert...

convert((1+x)^n,FormalPowerSeries,x);

## plot3D...

restart:c:=50;beta:=10;A:=0.01;L:=0.5;
y:= A*exp(-beta*(x-L-c*t)^2/(L^2));
plot3d(y,x=0..1.5,t=0..0.003,axes=framed,grid=[80,80]);

## keyboard shortcuts...

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

## DEPlot...

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

restart;
k:=2:M:=10*exp(-t/5)+3*(1-exp(-t/5)):
DETools[DEplot]( diff(y(t),t)=k*(1-y(t)/M)*y(t), y(t), t=0..20, [y(0)=1] );

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