LeeHoYeung

Mr. Ho Yeung Lee

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12 years, 235 days

Social Networks and Content at Maplesoft.com

Seldom to ask question after retired math hobby Welcome August, February, July, May born girl And waited for her email to mavio@protonmail.com

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These are questions asked by LeeHoYeung

 from galois group function's result?                                     

g[1] := (diff(a(t), t))/(t^2-1) = 1;
g[2] := (diff(a(t), t))*(diff(b(t), t)) = 1;
dsolve({eq2, eq3});
with(DynamicSystems):
sys := DiffEquation([g[1]=1, g[2]=1], inputvariable = [b(t)], outputvariable = [a(t), b(t)]):
ts := 0.1:
t_sim := 10.0:
#in_t := Sine(1, 1, 0, 0):
#in_z := Sine(1, 1, 0, 0, samplecount = round(t_sim/ts), sampletime = ts, discrete):
in_t := t:
sol := Simulate(sys, [in_t]):
p1 := plots[odeplot](sol, [[t, a(t)]], t = 0 .. t_sim, numpoints = 200, color = red):
Error, (in DEtools/convertsys) unable to convert to an explicit first-order system
Error, (in plots/odeplot) input is not a valid dsolve/numeric solution

would like to draw the graph of x^2-1

with below sys instead of x^2-1 

sys := {-(1/2)*(-x-1+sqrt(-3*x^2-2*x-3))*(diff(y(a, b), b))/x^2+(diff(y(a, b), a))*(diff(y(a, b), b)), (1/2)*(x+1+sqrt(-3*x^2-2*x-3))*(diff(y(a, b), a))/x^2+(x^2+x+1)/x^4, (1/2)*(x+1+sqrt(-3*x^2-2*x-3))*(diff(y(a, b), a))/x^2-(1/2)*(-x-1+sqrt(-3*x^2-2*x-3))*(diff(y(a, b), b))/x^2+(x^2+x+1)/x^4};
IBC:={x=1,y(a,3)=(3-1)*(3+1),y(0,b)=0,y(1,b)=0}:
pds:=pdsolve(sys,IBC,numeric,spacestep=140);
plots[display]([seq(pds:−plot(v,t=i10),i=0..5)]):

 

f2 := (diff(y(a, b), a)-(-(1/2)*x-1/2+(1/2)*sqrt(-3*x^2-2*x-3))/x^2)*(diff(y(a, b), b)-(-(1/2)*x-1/2-(1/2)*sqrt(-3*x^2-2*x-3))/x^2);
f := collect(expand(f2), [diff(y(a,b),a),diff(y(a,b),b),diff(y(a,b),a)*diff(y(a,b),b)]);

map(f, foldl(`*`, 1, a, b));
foldl(`*`, 1, map(f,a), map(f,b));

map(f, foldl(`+`, 0, a, b));
foldl(`+`, 0, map(f,a), map(f,b));

i discover it can auto calculate ring homomorphism, 

if i define a function f below

factor(map(f, foldl(`*`, 1, a, b))+map(f, foldl(`*`, 1, b, c))) = map(f, foldl(`*`, 1, a, c));

how to convert this f into a function with two input parameters?

 

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