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Hello everybody, please help me. I have a system of PDEs and I can't solve it. I have an error as:

"Error, (in pdsolve/numeric/par_hyp) Incorrect number of initial conditions, expected 3, got 2"

 

 

I want to obtain the exact (symbolic) solution of

240*t^3 + 144*t^2 - 135*t -52 =0

in the form  a+ b*I, where a, b are (symbolic) real numbers.

It is possible if I understand Wikipedia well.

"solve" gives "RootOf" and the "convert(......, radical)"  gives quantities such as

(9522 + 45*I* squarerootsymbol(226511))^(1/3)

Thanks.

 

Sorry for posting the question to two topics (here and there http://www.mapleprimes.com/forum/ihaveequationafterdsolvehowcaniuseonlyonepartitseewhensolutionbecomesequalsmth)

But it seems to me that it fits both of them.

________________

I have a differential equation.

ODE := diff(diff(x(t), t), t)+.2*(diff(x(t), t))-x(t) = sin(t)

ics := x(0) = .5, (D(x))(0) = 5

X1 := dsolve({ODE, ics})

So the solution is: 

I have a differential equation.

ODE := diff(diff(x(t), t), t)+.2*(diff(x(t), t))-x(t) = sin(t)

ics := x(0) = .5, (D(x))(0) = 5

X1 := dsolve({ODE, ics})

So the solution is: 

X1 := x(t) = exp((1/10*(-1+sqrt(101)))*t)*((111/404)*sqrt(101)+111/404)+exp(-(1/10*(1+sqrt(101)))*t)*(111/404-(111/404)*sqrt(101))-(5/101)*cos(t)-(50/101)*sin(t)

Now I need to find out when the solution becomes equal to 1.

But Maple of course does not understand when I write

Hi all

I'm having trouble with Maple and cancelling fractions properly. I will demonstrate. As you can see the method using sub and fractions doesn't work whilst directly copying it into a stacked fraction does. I can see that it must be to do with which fraction is the main one (largest bar) but if I put in my variables like they appear it changes and thus doesn't cancel properly.

I have also include the maple file with the actual problem in context if that helps.

Any help would be much appreciated.

I found the below text here :  scienceblogs.com/goodmath/2008/07/back_to_math_solving_zerosum_g.php

My question is how can I set up this problem in Maple ?!

The objective function should be: min(E(H1), E(H2), E(H3))
constraint:  Σpi=1, and ∀i: 0≤pi≤1.
solution: p1=0.57, p2=0.17, p3=0.26.

Hello,

I have an expression y, it comes from a calculation. I would like to simplify the argument of arctan in the expression using Maple. (This can be a part of a complicated expression, so I 'd like to automatize this procedure).

Assumptions: s0>0, w>0

y:=cos(w*t-arctan(2*s0^3*w, -s0^2*(-s0^2+w^2)));
 

Thank you for your help in advance.

 

 

 

Is there already a command to convert a higher order DEQ to a set of first order equations? Coeffs may be not neccessarily constant or polynomial in the independent variable. Example:

y'''-2*y''+x^2*y'+sin(x)*y-1=0

should convert to

X'=A*X+B

with A,B matrices and X,X' vectors of length 3
 

How do I make a phase plane diagram in Maple given the system needs to be solved implicitely? It's the implicit solving that is throwing me the curve ball....Any help is greatly appreciated! Thanks,

Nathan

Hi,

I am given the differential eqn : 4x'' +3x'+kx=0  with initial conditions  x(0)=0 and x'(0)=1

then I'm asked to:

display a Hooke's constant k>0 such that the solution x(t) is under-damped. Check that    x(t)=0  for infinitely many t>0. Display the exact solution x(t) obrained by maple methods.

I have this coin toss (see attached pdf and maple worksheet for further details)

"A fair coin is tossed, and the result is shown to player one. Player one must then decide
whether to pass or play. If player one passes, then he must pay player two $1. If player
one plays, then player two (who does not know the result of the coin toss) may either pass or play.
If player two pass, then he pays player one $1. If player two plays and the coin comes up heads,

hi!

two questions for the most expert among you:

question 1)

i want to evaluate a function A in a point identified by a number of variables that i have already numerically found from the solution of a sistem (let's say my solutions are S:={B=0.01, C=0.2, D:=0.3} ) but A also depends on another variable (Z) to which i want to assign a value

so i need to write eval(A,S) but also considering Z and it seems that eval(A,{S,Z=1}) doesn't work.

how do i tell maple to compute A considering both the solutions in S and Z=1?

question 2)

Hi:

exponentiating a matrix seems very slow. Consider this:

with(LinearAlgebra):

M:=RandomMatrix(10,10, generator=0.0..1.0):

st:=time():
MatrixExponential(M, -I*t):
time()-st;
                                   17.251

the same code takes ~0.1 second in MMA.

Any ideas why the following is giving me an error message?  Maple 14 WinXP 32 bit

restart:


with(DynamicSystems):


sys:=TransferFunction((0.04798*z+0.0464)/(z^2-1.81*z+0.9048),discrete=true,sampletime=0.1);

PrintSystem(sys);

Here is my problem. I have some data in excel format organized in three columns of x, y, z values. I am able to import the data in maple via the assistant tool and create a 3d surface plot. Now I would like to create a 2d contour plot on the x-y plane and possibly put the 3d surface and the 2d controur plot together. Do you think this is doable without changing the data format? I have looked for other posts, but none of them seems to highlight the data format problem. Thanks in advance, regards, Man
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