LeeHoYeung

Mr. Ho Yeung Lee

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12 years, 237 days

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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

-.733448502640020+0.*I

i am investigating above numeric

when ln(-.733448502640020+0.*I);

 

-.3099978916+3.141592654*I

it has Pi imaginary part

then 

i try 

complex(1, exp(Pi)^3);

it return Complex(...) but not 1 + i*exp(Pi)^3

 

3 means 3 times come from recursively  using pattern ln(Re(ln(x) - 3.141592654*I))

3.141592654 in imaginary part appear 3 times

i use Round(Im(x), 8) during above operation

 

 actually i want to extract Pi imaginary part from -.733448502640020+0.*I

 

however, after minus exp(Pi) from it first time,

it is near the original number  -.733448502640020

is this elimination of imaginary part is just a illusion from log function?

how to decompose a matrix into time invariant and time variant 

is it possible to make time invariant and time variant template and then decompose into it

 

i mean decomposition can be 

 time invariant matrix + time variant matrix

or

 time invariant matrix * time variant matrix

 dsolve([Diff(f, t) = f, Diff(f,t) + g = h], f);

 dsolve([Diff(f, t) = f, Diff(f,t)*g = h], f);

where h is orthogonal matrix, f,g,h are matrix

would like to find g and f from h

 

can dsolve solve differential equation of matrix ? how?

 

dsolve([Diff(f(t), t) = f(t), Diff(f(t),t) + g(t) = h1(x)*h2(x), int(h1(x)*h2(x),x=-1..1) = 0], [f(t),g(t),h1(x),h2(x)]);


dsolve([Diff(f(t), t) = f(t), Diff(f(t),t)*g(t) = h1(x)*h2(x), int(h1(x)*h2(x),x=-1..1) = 0], [f(t),g(t),h1(x),h2(x)]);

 

assume x^2 + 1 is from interpolation of polynomial

pdsolve([Diff(f(t), t) = f(t), Diff(f(t),t) + g(t) = h1(x,t)*h2(x,t), h1(x,t)*h2(x,t)= x^2+1], [f(t),g(t),h1(x,t),h2(x,t)]);
pdsolve([Diff(f(t), t) = f(t), Diff(f(t),t)*g(t) = h1(x,t)*h2(x,t), h1(x,t)*h2(x,t) = x^2+1], [f(t),g(t),h1(x,t),h2(x,t)]);

these system can not be solved

 

hope no real number any more after decomposition and only have iinteger in I time invariant function

if kernel is solve(A*x, x);

then , what is cokernel of a numeric matrix ?

assume f:= x^2*y^3/z^7

 

would like to get [x^2, y^3, z^(-7)]

f := x1^2/((x2^3)*(x3^2));

would like to extract 1/x2 from 1/(x2^3) and 1/x3 from 1/(x3^2)

and then assign 1/x2 to x2b and assign 1/x3 to x3b

and then replace 1/(x2^3) with x2b^3 and 1/(x3^2) with x3b^2 in f

 

only in this example has x2 and x3, in real case, it is unknown how many variables all division part

how to automatically to do above for equations with division

 

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