Hy all.

I want to solve this equation, with„dd” as numerical result. What do I do wrong? Thanks. Nico

restart;
TTot := 70;
TC := 17;
GM := .26;
QMax := 870;
V := 3600*GM*QMax*TTot;
eq := V = int(QMax*exp((-t+TC)/dd)*(1+(t-TC)/TC)^(TC/dd), t = 0 .. TTot);
fsolve(eq, dd);

Hello,

I'm trying to resolve a PDE using pdsolve().

The equation is :

diff(n(z,t),t)+diff(n(z,t)*v(z,t),z)=0

where n is the density of particles in a container and v their velocity.

I assume that the density decreases linearly at t=0 : n(z,0)=n[max]*(1-z/H) where H is the height of the container.

This gives the following system : 

> sys := [diff(n(z, t), t)+(diff(n(z, t)*v(z,t), z)) = 0, n(z, 0) = k_1*(1-z/H)]

With a velocity of the form :

v(z,t) = (1/tau)(1/n(z,t)-1/n[max])

it works like a charm.

However, I would like to try a velocity of the form :

v(z,t) = v[max]*(1-(n(z,t)/n[max])^5)

(similar to Greenshield model).

pdsolve() raises an error when I try :

> sys := [diff(n(z, t), t)+k_2*(diff(n(z, t)*(1-(n(z, t)/k_1)^5), z)) = 0, n(z, 0) = k_2*(1-z/H)];

> pdsolve(sys);

"Error, (in pdsolve/BC/1st_order/_Fn/integrate) invalid input: op expects 1 or 2 arguments, but received 0"

op(sys) returns the expected result, so I guess the problem comes from the power.

Have you guys have any solution ?

Thanks a lot.

Greetings everyone. I tried to get the roots of this polynomial by using allvalues command. But I got the roots in indeces instead of the value of the roots.

what should i do?

Hi all,

my problem concerns operation with complex number in Maple 18. The issue is the following:

i define this complex: c:=a+i*b

then i compute the square: sort(evalc(c^2))

and the output is: a^2+2*i*ab-b^2

So, how can i obtain an output like the following?  a^2-b^2b^2 +a*i*ab

In other word i want an output where the real part precede the complex part.

thank you in advance :)

Hi all. I am a new maple 18 user and Mapleprimes member.

1. I tried to plot y=x^2+2, but in the graph the value of y at x=0 is not 2(the bottom of the graph is near y=0). Same for the plot of just x^2+2(no y variable).

2. Why do I need to specify a y range for y=x^2+2? Why can't I just specify the x range only, since y is based on x?

Thanks in advance. :)

Maple has a powerful package for manipulation with logical expressions (Logic package). But it lacks for transfomation a boolean expression to algebraic normal form (ANF). In fact, this transfomation is very simple and implements by applying simple rules

to disjunctive normal form.

I suppose that this can be reached by introducing some custom operators and transfomations, if it is possible in Maple.

matlab has break point in loops which in extremely useful tool for finding errors in long term loops,whay maple does not has sth similiar !?

hi every one,i want to know what are the maple strentgh compraed to matlab and mathematica ? why someone should choose maple instead of these both ? i searched the net,but nothing useful has been found , tnx in advance .

How to identify whether biased game is changed based on the latest toss from a sequence

can HMM identify this?

for example

if

fair fair fair biased biased fair fair biased

Hi,

I have a system of diff equations (see below). I am trying to obtain analytical solution. when I assume that z=wN, I receive such solution. Do anybody have idea if I know that z>wN, does this system has an analytical solution?

diff(K(t), t) = -(1/2)*(Q(t)^2*alpha^2*eta*upsilon-2*eta*alpha*(N*upsilon*w*C[max]-z*alpha*K(t))*Q(t)+N*w*(-2*C[max]*z*eta*alpha*K(t)+upsilon*((-N*w+z)*alpha+N*C[max]^2*w*eta)))*K(t)/((C[max]*w*N-alpha*Q(t))*upsilon*N*w)

diff(Q(t), t) = (1/2)*(-z*(Q(t)^2*alpha^2*eta-2*N*Q(t)*alpha*eta*w*C[max]+w*(w*(eta*C[max]^2-alpha)*N+z*alpha)*N)*K(t)-2*N*upsilon*w*(N*w-z)*(C[max]*w*N-alpha*Q(t)))/((C[max]*w*N-alpha*Q(t))*upsilon*N*w)

K(0) = K0, Q(0) = Q0

Thanks,

Dmitry

Hi all,

I would like to set equal to zero some monomials in a polynomial. In particular those monomials in which an unknown has a certain degree. 

For example for the polynomial

poly := x^2*y+x*y*z+x*z

i would like to set equal to zero the monomials in which x has degree 1, that is x*y and x*z.

Is there a way to do it?

Thanks in advance
Manuele 

http://www.math.uni-frankfurt.de/~numerik/maplestoch/

read "D:/diffalg03/stochastic9";
Sigma := `<,>`(`<|>`(1.0, .5), `<|>`(.5, 1.0));
V := WienerProcess(Sigma);
Z := t -> exp(a*t+b*V(t)[1]+c*V(t)[2]);
drift1 := simplify(Drift(Z(t))/Z(t));
diffusion1 := simplify(Diffusion(Z(t))/Z(t));
with(stochastic);
linearsde(drift1, diffusion1[1][1]);
Euler(x[1],drift1,diffusion1[1][1]);

1.what are a, b, and c?

2. how to convert SDE for monte carlo for this ito formula?

3. how to convert to euler scheme with this ito formula

Hello fellow maple users,im new to the software,im trying to solve a differential system but it dosent work

This is the system :

DE1 := diff(Y(t), t) = 5*Y(t)*ln(b(t)/Y(t))-5*Y(t)

DE2 := diff(b(t), t) = 5*b(t)*Y(t)^(3/2)-5*Y(t)

Thank you for your help !

I have a function f(X,Y) and I create a random sequence of input values for X and Y.

I now want to create a 2D scatter plot with X and Y on the axis, on the graph I want each point (X,Y) to be color coded according to the value of f(X,Y).  For example, 0<f<1 Red, 1<f<2 Blue, 2<f<3 Green.

Does anyone know how I could do this? 

sin(xy) = x + y

subs( y(x)=y, solve( diff(subs( y=y(x), (1) ),x), diff(y(x),x) ) );

-1

subs( x(xy)=x, solve( diff(subs( x=x(xy), (1) ),xy), diff(x(xy),xy) ) );

cos(xy)

I can not get this answer to come out correctly when using this software please help. the correct answer in the back of the book is 

1- y cos(xy)

--------------

x cos(xy) - 1

And is there a way that this program can tutor me on how to get this answer intead of spitting out the answer 

the diff tutor only allows for a one sided equation to be entered.