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gkokovidis

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20 years, 289 days
Draeger Medical Systems, Inc.
Contact gkokovidis

 

 

Regards,
Georgios Kokovidis
Dräger Medical

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These are answers submitted by gkokovidis

?Export...

gkokovidis 2370
June 02 2012
0 0

See help page here.

 

Regards,

Georgios Kokovidis

Dräger Medical

alias...

gkokovidis 2370
June 01 2012
0 0

Look at the help page for the ?alias command for details.  Does the example below meet your needs?

> 

restart:
> 

diff(P(x, tau, p), p);

diff(P(x, tau, p), p)

  (1)
> 

v[1](x, tau);

v[1](x, tau)

              (2)
> 

cc:=2*(D[2](v[0]))(0, tau)*(diff(eval(diff(P(x, tau, p), p), p = 0), x))/(1-v[0](0, tau));

2*(D[2](v[0]))(0, tau)*(diff(eval(diff(P(x, tau, p), p), {p = 0}), x))/(1-v[0](0, tau))

 (3)
> 

alias(v[1](x, tau)=diff(P(x, tau, p), p));

v[1](x, tau)

                                                                    (4)
> 

cc;

2*(D[2](v[0]))(0, tau)*(diff(eval(v[1](x, tau), {p = 0}), x))/(1-v[0](0, tau))

 (5)
> 

 

Download alias.mw

Regards,

Georgios Kokovidis

Dräger Medical

Fit...

gkokovidis 2370
May 30 2012
0 0

While the detailed math relationship can be found in the picture,
extracting detailed data pairs is rather difficult.  
A digitizing program that generates x-y pairs could be used.  
The more data, the better the fit.  Fitting the picture with a simple math function,
without using piecewise or splines is not straight forward.  
Below is a very rough attempt to do so by estimating x-y pairs.

restart: with(plots):
with(Statistics):
X := Vector([1, 25,50,75,100, 125,200, 300, 400, 500, 600]):
Y := Vector([40e3,8e3, 2000,600,350, 210,200, 180, 170, 150,140]):
eq:=NonlinearFit(a+b*exp(-c*t)+d^(-t), X, Y, t);
logplot(eq,t=0..600,y=1..100000,gridlines=true);

nonlinearfit.mw

Regards,

Georgios Kokovidis

Dräger Medical

save and read...

gkokovidis 2370
May 24 2012
1 1

The save command, as implemented below, will write to the directory that the file lives in.  You can change this to whatever you like.

> 

restart:
> 

with(plots):
> 

sol1:= dsolve({D(y)(x) = y(x), y(0)=1}, y(x),type=numeric):
> 

p1:=odeplot(sol1,[x,y(x)],-1..1 ):
> 

sol2:= dsolve({D(y)(x) = 2*y(x), y(1)=1}, y(x),type=numeric):
> 

p2:=odeplot(sol2,[x,y(x)],-1..1,color=blue):
> 

dd:=display(p1,p2):dd;

 
> 

save(dd,`hill2.m`);
> 

 

> 

restart:
> 

dd;

dd

                                (1)
> 

read(`hill2.m`);
> 

dd;

 
> 

 

Download odeplot_display_save.mw

Regards,

Georgios Kokovidis

Dräger Medical

eval...

gkokovidis 2370
May 23 2012
1 0

See ?eval for more help, if this is what you are trying to do.

> 

restart:
> 

T[2]:=2*x^2-1;

2*x^2-1

  (1)
> 

eval(T[2],x=2);

7

                           (2)
> 

 

Download eval.mw

 

Regards,

Georgios Kokovidis

Dräger Medical

?display...

gkokovidis 2370
May 22 2012
1 4

You can combine plots using ?display.  One way to do this with dsolve/numeric is shown below.

> 

restart:
> 

with(plots):
> 

sol1:= dsolve({D(y)(x) = y(x), y(0)=1}, y(x),type=numeric):
> 

p1:=odeplot(sol1,[x,y(x)],-1..1 ):
> 

sol2:= dsolve({D(y)(x) = 2*y(x), y(1)=1}, y(x),type=numeric):
> 

p2:=odeplot(sol2,[x,y(x)],-1..1,color=blue):
> 

display(p1,p2);

 
> 

 

Download odeplot_display.mw

 

Regards,

Georgios Kokovidis

Dräger Medical

Bug...

gkokovidis 2370
May 16 2012
2 1

Looks like a bug.  As a workaround, you could use the deprecated version of "Array", which is "array".

 

 

Regards,

Georgios Kokovidis

Dräger Medical

Physics: Puck On a Frictionless Table...

gkokovidis 2370
May 11 2012
0 1

Like this, or something else?  See here for more help on parametric plots.

> 

restart
> 

x[0] := 1;Omega := 1;v[x0] := 0;v[y0] := 1

1

  

1

  

0

  

1

 (1)
> 

xp := (x[0]+v[x0]*t)*cos(Omega*t)+(v[y0]+Omega*x[0])*t*sin(Omega*t)

cos(t)+2*t*sin(t)

 (2)
> 

yp := -(x[0]+v[x0]*t)*sin(Omega*t)+(v[y0]+Omega*x[0])*t*cos(Omega*t)

-sin(t)+2*t*cos(t)

 (3)
> 

plot([xp, yp, t = 0 .. 10*Pi], -10 .. 10, -10 .. 15)

 
> 

 

Download puckontable2.mw

 

Regards,

Georgios Kokovidis

Dräger Medical

Maple version...

gkokovidis 2370
May 06 2012
0 0

What you are describing will not work in the Classic Interface, but will work in the Standard Interface.  For this example, I used Maple 15.

> 

restart:
> 

with(plots): y1:=0.01*sin(Pi/2*x-40*Pi*t);

-0.1e-1*sin(-(1/2)*Pi*x+40*Pi*t)

               (1)
> 

y2:=0.01*sin(Pi/2*x+40*Pi*t);

0.1e-1*sin((1/2)*Pi*x+40*Pi*t)

                      (2)
> 

y:=y2+y1;

0.1e-1*sin((1/2)*Pi*x+40*Pi*t)-0.1e-1*sin(-(1/2)*Pi*x+40*Pi*t)

 (3)
> 

animate(plot,[y1,x=0..10,legend="testing"],t=0..5,frames=50);

 
> 

 

 

Download legend.mw

 

Regards,

Georgios Kokovidis

Dräger Medical

printlevel...

gkokovidis 2370
April 25 2012
1 0

Not exactly step by step, similar to some of the tutorials, but there is info that is useful here.  See ?printlevel for more details.  The higher the number, the more verbose the output.

> 

restart:
> 

printlevel:=2:
> 

f:=k!/(k+t)!;

factorial(k)/factorial(k+t)

 (1)
> 

S[n,t]:=sum(f,k=0..n-1);

-(n+t)*factorial(n)/((t-1)*factorial(n+t))+t/((t-1)*factorial(t))

 (2)
> 

restart:
> 

printlevel:=10:
> 

f:=k!/(k+t)!;

{--> enter _factorial, args = k

  

factorial(k)

  

<-- exit _factorial (now at top level) = factorial(k)}
{--> enter _factorial, args = k+t

  

factorial(k+t)

  

<-- exit _factorial (now at top level) = factorial(k+t)}

  

factorial(k)/factorial(k+t)

 (3)
> 

S[n,t]:=sum(f,k=0..n-1);

{--> enter _factorial, args = k

  

factorial(k)

  

<-- exit _factorial (now at top level) = factorial(k)}
{--> enter _factorial, args = k+t

  

factorial(k+t)

  

<-- exit _factorial (now at top level) = factorial(k+t)}
{--> enter sum, args = factorial(k)/factorial(k+t), k = 0 .. n-1

  

k = 0 .. n-1

  

[[factorial(k)/factorial(k+t), k, 0, n-1], false, FAIL]

  

{}

  

-(n+t)*factorial(n)/((t-1)*factorial(n+t))+t/((t-1)*factorial(t))

  

<-- exit sum (now at top level) = -(n+t)*factorial(n)/((t-1)*factorial(n+t))+t/((t-1)*factorial(t))}

  

-(n+t)*factorial(n)/((t-1)*factorial(n+t))+t/((t-1)*factorial(t))

 (4)
>   

Download sum.mw

 

Regards,

Georgios Kokovidis

Dräger Medical

?numboccur...

gkokovidis 2370
April 23 2012
1 0

See help page for ?numboccur.

 

Regards,

Georgios Kokovidis

Dräger Medical

Complex Number - Engineering Form?...

gkokovidis 2370
April 14 2012
0 0

Yes.  See the following thread.

 

Regards,

Georgios Kokovidis

Dräger Medical

Student[Precalculus][LineTutor]();...

gkokovidis 2370
April 07 2012
0 0

I do not have Maple 13 installed, but I think this is available.  Look at the help page for:

?Student[Precalculus][LineTutor], or click on the  Tools, Tutors, Precalculus, Lines... tab, and a GUI should pop up allowing you to do what you are looking for.

Regards,

Georgios Kokovidis

Dräger Medical

solve returns a strange answer...

gkokovidis 2370
March 30 2012
0 0
> 

restart:
> 

x/3=(x+0.2)/15+1.5;

(1/3)*x = (1/15)*x+1.513333333

 (1)
> 

solve(%,x);

5.674999999

                                 (2)
> 

convert(%,rational);

227/40

                                                 (3)
> 

 

> 

 

> 

restart:
> 

x/3=(x+0.2)/15+1.5;

(1/3)*x = (1/15)*x+1.513333333

 (4)
> 

convert(%,rational);

(1/3)*x = (1/15)*x+227/150

                 (5)
> 

solve(%,x);

227/40

                                                  (6)
> 

evalf(%);

5.675000000

                                    (7)
> 

 

Download rat_solve.mw

 

Regards,

Georgios Kokovidis

Dräger Medical

Paste option as described by Joe...

gkokovidis 2370
March 27 2012
0 0

The paste option, in the DOS box will work.  The characters ">" will need to be removed in front of every line:

MEMBER := proc(x::anything, L::list, p::evaln) local i;
for i to nops(L) do
if x=L[i] then
if nargs>2 then p := i end if;
RETURN(true)
end if
end do;
false
end proc

Regards,

Georgios Kokovidis

Dräger Medical

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