Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

Hi I have three differential equations: 

u := diff(P(t), t) = -7*10^(-8)*P(t)*t/(P(t)*t+R(t))^(1/2),

diff(R(t), t) = 7*10^(-8)*t^2*P(t)/(P(t)*t+R(t))^(1/2)+600*(Z(t)^2-10^5*t^3*(1/(1.15*10^12))^(2/3)*e^(-1.15*10^12))/(t*(P(t)*t+R(t))^(1/2)),

diff(Z(t), t) = -4*10^5*(Z(t)^2-10^5*t^3*(1/(1.15*10^12))^(2/3)*e^(-1.15*10^12))/(t^2*(P(t)*t+R(t))^(1/2))

 

and i want to solve them with initial conditions:

initial := R(0) = 0, Z(0) = 0, P(0) = P;

Hello and thank you in advance,

I am used to Mathematica and am looking to switch, conditionals in Mathematica seem easy, like say

 

  If[0 < z && -6 <= y <= 6 && 0 < x < 1             ,Null             ,Return[0]];

 

How do you replicate this in an easy to read way without lots of nested if statements?

Hi,

 

r:=[3,3,3,3,4,4,4,3,3,3,3,3,3,3,3,2,4,3,1];

 

What's the shortest way to create a frequency table from it?

 

Ie, tells me elements are 1,2,3,4

the corresponding counts are: 1,1,13 and 4

and then if it can return the number with highest counts: 3

Many thanks!

Casper

Hellow, can any body give the suggestion regarding multiple plot in array

i have 

V:=(2*x+3*gamma)*y^2

d0:=subs(x=0.1,gamma1=0,V):
d1:=subs(x=0.1,gamma1=2,V):
d2:=subs(x=0.1,gamma1=4,V):
plot([d0,d1, d2], y=0..0.1,  legend = ["gamma = 0", "gamma= 2","gamma= 4"], titlefont = ["ROMAN", 15], labels = ["y ", "v"], labeldirections = ["horizontal", "vertical"], labelfont = ["HELVETICA", 10], linestyle = [solid, longdash,dashdot],color = [black, red,green], axesfont = ["HELVETICA", "ROMAN", 8], legendstyle = [font = ["HELVETICA", 9], location = bottom],axes=boxed);

 
and 
e0:=subs(x=0.5,gamma1=0,V):
e1:=subs(x=0.5,gamma1=2,V):
e2:=subs(x=0.5,gamma1=4,V):

 
plot([e0,e1, e2], y=0..0.1,  legend = ["gamma = 0", "gamma= 2","gamma= 4"], titlefont = ["ROMAN", 15], labels = ["y ", "v"], labeldirections = ["horizontal", "vertical"], labelfont = ["HELVETICA", 10], linestyle = [solid, longdash,dashdot],color = [black, red,green], axesfont = ["HELVETICA", "ROMAN", 8], legendstyle = [font = ["HELVETICA", 9], location = bottom],axes=boxed);

 
I want to display  this side by side  i,e set {do,d1,d2} and {eo,e1,e2} 

 
 thanks in advance


 
 exa.doc

Hi, I am trying to plot a solution curve on a vector field with an initial condition of y(0)=0 and I keep getting error messages. This is what I have so far:

 

with(DEtools); dfieldplot(diff(y(x), x) = x^2+y(x)^2-1, y(x), x = 0 .. 5, y = -1 .. 5, arrows = line, title = 'Slope*Field');

 

Thank you. 

Greetings,

I have a finite Fourier series of the form, Asin(x)cos(z) + Bsin(2x)cos(z) + Csin(3x)cos(2z) +... I would like to be able to extract the coefficients, A,B,C etc., that correspond to a specific mode. I have tried using the coeff and coeffs functions. They work for a one-dimensional Fourier series (i.e. if S= Asin(x) + Bsin(2x) + Csin(3x); is my series, then coeff(S,sin(2x) returns B). I cannot however get this to work for the 2-D case. Any suggestions?

Hello, I'm currently trying to approximate the solution of a PDE with Maple, but I'm having troubles with the boundarie conditions .
For instance, when I set : (dT/dr)(r=3,t) = 0 , everything works fine .

With (dT/dr)(r=3,t) = -T(r=3,t), it's still okay .
But if I set (dT/dr)(r=3) = -T(r=3,t)^4, Maple just ignores the second member and works as if it was 0 . There is no error notification, but I don't get a satisfying solution ..

I have occasionally a need to map a function over the components of an expression; but not just at the top level---which map() does---but to an arbitrary level. One application is e.g. to throw simplify at subexpressions of a complicated object. Sooner or later I will want to specify the deepest level also... I looked through the docs and Help but could not find anything like that. I had expected map[n]() to do something like this, but it does not.

Does Maple have a...

Dear Maple users

We are using Maple at our school. Usually activation with the Activation code works well if the computer has a good connection to the Internet. Our data instructor have however experienced a problem with two computers he cannot seem to solve. He is not able to activate Maple 16 on those computers. After a failure in activation he even reset the license.dat file. Maybe someone have an idea to how we can get those computers activated and what the problem...

hello every body

how can i solve this equation with respect to z

a, b are constants

3a(1+z)^2=2(a(1+z)^3+b)^(1/2)

Dear experts, I have problems about "subs", see below
> restart:
> assume(A>0): interface(showassumed=0):
> f:= A^2-2*sqrt(A^2+1)+1;
Now I want to replace A^2+1 to M^2, so idealy, what I want to see is
M^2 + M
 
When I do:
> f2:= subs(A^2+1 = M^2,  f);
Maple shows 
A^2-2*sqrt(M^2)+1
Maple cannot replace A^2+1
 

I have a very large system of rather long equations.   I need to find a way to have maple recognise if two equations within the system are the same.  I've been attempting to do this by adding each of them to the same set.  Maple automatically eliminates two identical entries in a set, so this works quite well for, say, x+y=0 and y+x=0 - maple knows these are the same and deletes one from the set automatically.  However it does not recognise that x+y=0 is the same as 2x + 2y = 0.

Well, it’s been more than 17 years since First Leaves: A Tutorial Introduction to Maple V was first published as a hardcover book, and since that time, Maple, the Maple documentation, and the world have undergone huge changes.   We are now in a state where all our documentation is available electronically, including both in-product and online; where the vast majority of our customers receive our products electronically and never even see the printed...

Although unfinished, this project I had left idle for a while and just thought to share with the community.  Not fancy by any means, no graphs or anything, was just having fun creating a worksheet on mortgages but then ran out of free time to work on things as usual, anywyas.  I skipped the derivation for the formula after n payments at the end and just provided the formula and dove right into an example.  For interest, my applications usually have numbers after...

Hello all,

I have the state-space form of a dynamics sytem:

X_dot = AX+B.U

Y= C X,

The initial conditions of the outputs (Y0) are also given.

A is 7x7 known matrix,

C is 14x7 known matrix,

B = 0;

The problem is that it's too long to write down every equations (14+7 eqns) and variables in "dsolve" function

Would you please show me the shorter way to solve a very large state-space system?

I really appreciate your help.

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