Dear all,

I am trying to solve a differential equation like the one below:

f := y(x)+5*(diff(y(x), x))+2*x^3*(eval(diff(y(x), x), x = 0))+3*y(0)

however, because of having y(0) in the quation, I get the error below:

Error, (in dsolve) found the indeterminate function y with different arguments {y(0), y(x)}

does anyone know how I could solve this?

Suppose that I have the equation x=1. I want to manipluate it. For example, I want to multiply by 2. Then, Take the power of two. Next, take a cubic root. How can I do this in Maple?

Qu_in_maple.mw

How to compute the  n component of U[i] even to reach the exact solution?

Download Qu_in_maple.mwQu_in_maple.mw

How to find the  n component of U[i] even to reach the Exact solution cos(x)

I am trying to solve 4 nonlinear equations for four variables using fsolve  and the output that i am getting is basically the same equations repeated after some time.  I even tried reducing one of the equations using assumptions from my side but it results in same behaviour..  Quite new to maple, would like some advice as to this behaviour. Thanks

 Here's the file

fsolve_1.mw

PS- using do loop is part of the solving so i cannot remove that

I am not seeing any reference in help to TRDPolynomial_ring in PolynomialRing function in RegularChains. Though if I debug it, I can get in it. Is it that it is part of kernel ?

Hi all

I need to convert int matrix into matrix over finite field.

E.g: Convert inform integer number

      A := <140, 155, 162, 64;

               218, 12, 245, 50;

                36, 251, 34, 253;

                171, 251, 184, 37>;

 into B = <x^7+x^3+x^2,x^7+x^4+x^3+x+1,x^7+x^5+x, x^6;

             x^7+x^6+x^4+x^3+x, x^3+x^2, x^7+x^6+x^5+x^4+x^2+1, x^5+x^4+x;

            x^5+x^2, x^7+x^6+x^5+x^4+x^3+x+1, x^5+x, x^7+x^6+x^5+x^4+x^3+x^2+1;

            x^7+x^5+x^3+x+1, x^7+x^6+x^5+x^4+x^3+x+1, x^7+x^5+x^4+x^3, x^5+x^2+1>;

(Matrix B over finite field GF(2^8)/f(x) =x^8 + x^6 +x^5 +x^3 +1) 

Thanks alot.

Dear all,

I like to plot a function, let's say x^2 in a boxed axis mode; i.e. 

plot(x^2,axis=boxed)

Howeve, I want the plot to have tickmarks on all four axises, and not only the normal x and y axis.

Can anyone help me with this please? 

plotpoints.mw

I want to plot points when i_t =1,2,3,..,11,12 instead of a continous line displayed in the worksheet I uploaded. How to modify the function? Thank you for helping:)

How to  compute the recurrence relation and I find the problem when the summation of U because appear noise term self-canceling and I can not find the nth component of U?Mixed_volterra_-Fredholm_(278)_Ex(8.17).mw

Download Mixed_volterra_-Fredholm_(278)_Ex(8.17).mwMixed_volterra_-Fredholm_(278)_Ex(8.17).mw

thank you for helping:)

Hello,

I have an non coupled non linear oscillator.

I notice that, if I try to plot for a time too big, my plot doesn't converge anymore and didn't keep an elliptic trajectory. In other words, the plot didn't stay in the limit cycle.

Do you know why, if tmax is too big, the solution is no longer stable ? Do you have ideas so that I can keep a stable limit cycle even if I increase tmax ?

My code is the following :

r:=sqrt((x(t)/a)^2+(z(t)/b)^2);
eqx:=diff(x(t),t)=alpha*(1-r^2)*x(t)+w*a/b*z(t);
eqz:=diff(z(t),t)=beta*(1-r^2)*z(t)-w*b/a*x(t);
EqSys:=[eqx,eqz];

params := alpha=1, beta=1, a=0.4, b=0.2, w=1;

EqSys := eval([eqx,eqz], [params]);
xmax := 0.8; zmax := 0.4;
tmax := 400;
ic:=[x(0)=0.4, z(0)=0];
DEplot(EqSys, [x(t),z(t)], t= 0..tmax, [ic],linecolor=black, thickness=1,x(t)=-xmax..xmax, z(t)=-zmax..zmax, scaling=constrained,arrows=none);

Thanks a lot for your help.

How to evaluate The Abel integral has the form I can not compute this

> restart;

> f := proc (x) options operator, arrow; (4/3)*x^(3/2) end proc; k := proc (x, t) options operator, arrow; 1/sqrt(x-t) end proc;

> int((4/3)*t^(3/2)/sqrt(x-t), t = 0 .. x);

Thank you :)

> restart;> f := proc (x) options operator, arrow; (4/3)*x^(3/2) end proc; k := proc (x, t) options operator, arrow; 1/sqrt(x-t) end proc;> int((4/3)*t^(3/2)/sqrt(x-t), t = 0 .. x);

I want to plot the curve of a pythagorean quadruple. Any suggestions? I think I have to use space curve. I never liked the options for color on those though. I'm guessing it's just a single curve based on what I know about these things. I have no idea what to expect but I'm sure it will please me no matter what.

X=2*m*p/(m^2+n^2+p^2)

y=2*n*p/(m^2+n^2+p^2)

z=(p^2-(m^2+n^2))/(m^2+n^2+p^2)

using FDM or FEM rather than dsolve?

ode.docxode.docx

Hello everyone! I'm currently trying to plot the effective potential for Sun-Jupiter system, to show the lagrangian points in this system. I've converted to a system of units where G=1, m_sun+m_jupiter=1 and R=1, whereby I get the following equation describing the effective potential of a third mass m in the system:

U(x,y)=-1 * 0.999047/abs(sqrt((x-(-0.000953))^2 +y^2 ))-1 * 0.000953/abs(sqrt((x-0.999047)^2 +y^2 ))

However, when I plot this in Maple, I don't get a contour plot that matches up with what I would [expect](https://upload.wikimedia.org/wikipedia/commons/thumb/e/ee/Lagrange_points2.svg/2000px-Lagrange_points2.svg.png), but [this](http://imgur.com/oZLE3gV). Is there possibly anyone here who could point out a mistake I've done, or give me some advice? Thanks in advance!

Occasionally I have need to import 1D Maple expressions into Mathematica, because I believe mma has superior simplify functionality (sorry Maple). Mathematica has its own syntax which (of course) differs to maple.  eg sin(x) in maple is Sin[x] in mma ; ln(x)=Log[x] ;....... I'm aware of the package MmaTranslator, but I think it only converts mma to maple.

so i need some code pls.

(i have bolded the functions which need to be converted)

eg: i/p:

(1/365)*(365*B21*EP*ln(1+i)*(1+i)^B21*hr*kw*p-365*EP*hr*kw*p*(1+i)^(-1+B21)*i-365*EP*hr*kw*p*(1+i)^(-1+B21)+365*EP*hr*kw*p+SC*i)/(hr*kw*(EP*ln(1+i)*(1+i)^B21*p-FIT*i*p+cos(omega)))

o/p:

(1/365)*(365*B21*EP*Log[1+i]*(1+i)^B21*hr*kw*p-365*EP*hr*kw*p*(1+i)^(-1+B21)*i-365*EP*hr*kw*p*(1+i)^(-1+B21)+365*EP*hr*kw*p+SC*i)/(hr*kw*(EP*Log[1+i]*(1+i)^B21*p-FIT*i*p+Cos[omega]))