Hi,

I'm trying to make a phase plane plot for the Lorenz system of differential equations around the equilibrium point (0,0,0) but when it keeps coming up with an error, saying it's "unable to obtain field plot, additional unknown(s) found: xy"

Any idea where I'm going wrong? Any help would be greatly appreciated!

Katie

sys1 := [diff(y(x), x) = a/(1-y(x))^b+c*exp(-d*x)/(1-y(x))^2]:

dsolve(sys1)

but the result is empty.

What can I do?

Hi all,

Is there any way to fill in colour to a polar plot using Maple 16? What I want to do is essentially make a coloured in pie slice using a defined radius and theta range.

I am aware of the function filled, which adds colour starting from the x-axis but that is not appropriate in this situation. I know of the filledregions function but that only works for implicit and contourplot, and as of yet I have not been able to use implicit...

g1 := [0, y, x];g2 := [0, y^2-x-y, 0]; g3 := [x, x+y, 0]; g4 := [y, -y, 0]; g5 := [0, x*y+x/2+y/2, 0]; g6 := [0, x^2-x/4-y/4, 0];

g1 := 0; g2 := 0; g3 := x; g4 := y; g5 := 0; g6 := 0;

restart; with(Groebner):

IsNullZero := proc(tau) if assigned(tau) then return tau else return 0 end if end proc;

Which command is similar with IsNull function in VBA for assign 0 when detect not assigned

I want to find shortest time it takes particle to travel from point A(0,0) to B(1,1). I tried to solve this problem by using following code test.mw. I know that solution to this problem is cycloid and i already found its equations in parametric form.

My problem is that when i try to solve integral as a solution i receive Time := Float(infinity)*I.

Is there any way to get a numeric solution in Maple...

Are There  options to solve this problem?

I solved a PDE system and got module() export plot,plot3d,animate,value,settings; ... end module (Got ui(x,t) and ur(x,t))
And after it I try to solve the task
Xs := [0, .175, .789, 1.818, 3.287, 5.183];
n := 1;
interface(prettyprint = 1);
for t1 from 0 by 50 to 50 do
k1 := sol:-value(t1, output = listprocedure);

(b0*z^n+b1*z^(n-1) + ... + bn) / (a0*z^n+a1*z^(n-1)+... + a_n_minus_m*z^m)

expand
into

beta0 + beta1*(1/z) + ... + betam*(1/z^m) + beta_m_plus_1*r_m_plus_1(z)/a(z) + ... + betan*rn(z)/a(z)

maple 17 does not calculate the definite integral  (?):

f(x):=sin(sin(x)); int(f(x), x = 0 .. 1).    

Trying evalf leads to the correct  numerical result.

> de := (1/4)*U*(diff(S(y)^4, `$`(y, 2))) = C*P1*((O*exp(G*y)-R*exp(J*y))/(P1*(exp(J*L)-exp(G*L)))+P2/P1);

print(`output redirected...`); # input placeholder
/ 2 \
1 | 2 / d \ 3 / d / d \\| /
- U |12 S(y) |--- S(y)| + 4 S(y) |--- |--- S(y)||| = C P1 |
4 \ \ dy / \ dy \ dy /// \

O exp(G y) - R exp(J y) P2\
------------------------ + --|

Help me please, How to get a spatial derivative?After solving a system of differential equations numerically, I got module.Help please, How can I find a  value of the first derivative? 
For example , after solving the PDE system, module() export plot,plot3d,animate,value,settings; ... end module
 So, I need to find diff(U(x,t),x) (for example x=0 and t=0) 

hi

how r u

i am writting this commands for loop but its not working .

i want to write genralize matrix for M and K

> Digits := 100;
> n := 4;
> y := vector([1, 1, 1, 1, 1, 1, 1, 1]);
> results := matrix(n, 3);
> for i to n do a1h := Generate; M := Matrix([[2, 3, 0], [0, 1, 7], [3, 1, 2], [2, 1, 0], [0, 0, 1], [3, 7, 0], [1, 1, 1], [5, 1, 0]]); m := `.`(1/(`.`(M^%T, M)), M^%T); mm := `.`(m, y); results[i] := m^%T end do;

I have a set X={a,b,c,d,e} and a table as follows:

M[2]:=TABLE([e = {2,3}, a = 5, c = 1]);

Afterwards I want to add to this table all those elements (e.g. b={3,4} and d=4) of X which are unassigned in M[2]. How I can do this?

Please help me with transformation of the following expression:

> z:=abs(a)^2*b+abs(a)^2*c*conjugate(a);

where I want to derive

a*(conjugate(a)*b+conjugate(a)^2*c)

I try the following:

> z:=collect(z,a);

However it does't transformate z in any way.

In other words if I have
>z:=a*conjugate(a);

>z:=simplify(z);

I derive z=|a|^2. How to decompose z back into a*conjugate(a)?

Hello

I have a nasty definite integral to evaluate. I need to integrate w.r.t X[2] and leave the integrated expression as a function of   X[1].

The discretization is via the...