Pepini

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1 years, 187 days

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These are questions asked by Pepini

Hi! Do you know maybe how to solve equation with Laplace operator in Maple like BZ equation?

restart;
a := 0.75;
rho := u(t) + v(t) + w(t);
ode := diff(u(t), t) = 10*Delta(u(t)) + u*(-a*v - rho + 1);
ode1 := diff(v(t), t) = 10*Delta(v(t)) + v*(-a*w - rho + 1);
ode2 := diff(w(t), t) = 10*Delta(w(t)) + w*(-a*u - rho + 1);

 

Edit: Sorry I guess it should be function of three variables so u,v,w depends on (x,y,z) not strictle from time

I am wondering how to animate something like this from BZ equation:

Hi! do you know any effective method to count area under this function given by dataset points? (I counted this by approximation by trapezes)

Edit: PolyFit is ok the best what I have done

Edit2: triangulation is the best (just add all triangles)

Hi! Do you know how to divide this array from .txt data to take separately these numbers? (I have over one thousands of these so I don't want to rewrite)

PS this is 1x1 I want to make 1x8

["0,00244140625;8,07751097960625;-3,555908203125E-05;0,002166748046875;1;1;0,0056941700604248;-0,0101856454842773;100 µA"]

restart;
g := 9.81;
with(DEtools);
with(plots);

odeplot(dsolve({diff(x(t), t, t) = 0, diff(y(t), t, t) = -g + y(t)^2, x(0) = 1, y(0) = 0, D(x)(0) = 0, D(y)(0) = 0}, numeric), numpoints = 1000);

Hi, do you know why this plot is ragged? and my second question do you know how to get a single function x(t) or y(t) from this numeric solution instead getting parametrization plot [x(t),y(t)]? Thanks in advance.

restart;
with(plots);
g := 32.2;
k := 0.1;
theta := Pi/5;
v := 50;


ode0 := diff(x(t), t $ 2) = 0, diff(y(t), t $ 2) = -g    

                                  
ode1 := diff(x(t), t $ 2) = -k*diff(x(t), t) - x(t) - 1/6*x(t)^3 + 1/120*x(t)^5, diff(y(t), t $ 2) = -g - k*diff(y(t), t) - y(t) - 1/6*y(t)^3 + 1/120*y(t)^5

ics := x(0) = 0, y(0) = 0, D(x)(0) = v*cos(theta), D(y)(0) = v*sin(theta)


dsolve([ode1, ics], numeric)

dsolve([ode0, ics])


display(plot([rhs(dsolve([ode0, ics])[1]), rhs(dsolve([ode0, ics])[2]), t = 0 .. 2], color = red), plot([rhs(dsolve([ode1, ics, numeric])[1]), rhs(dsolve([ode1, ics, numeric])[2]), t = 0 .. 2]), view = [0 .. 75, 0 .. 15])

 

Hi! Do you know maybe how to get this plot of ode1? I guess that computations are ok but I cannot get this plot.

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