## How I can solve these equations...

how I can solve these equations?

Fung.mws

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 > restart:
 > with(LinearAlgebra):
 > with(VectorCalculus):
 > Q:=a_11*(E_r)^2+a_22*(E_theta)^2+a_33*(E_z)^2+2*a_12*E_r*E_theta+2*a_13*E_r*E_z+2*a_23*E_theta*E_z:
 > psi:=0.5*c*(Q+0.5*Q^2):
 > F:=matrix([[B*R/r,0,0],[0,r/R,0],[0,0,1/B]]):
 > #b:=matrix([[B^2*R^2/r^2,0,0],[0,r^2/R^2,0],[0,0,1/B^2]]):
 > b:=matrix([[B*(r^2-A)/r^2,0,0],[0,B*r^2/(r^2-A),0],[0,0,1/B^2]]):
 > sigma_r:=-p+diff(psi,E_r)*b[1,1]:
 > sigma_theta:=-p+diff(psi,E_theta)*b[2,2]:
 > sigma_z:=-p+diff(psi,E_z)*b[3,3]:
 > #H:=p_o+subs(r=r_o,diff(psi,E_r)*b[1,1]):
 > H:=p_o+subs(r=sqrt(B*(R_o)^2+A),diff(psi,E_r)*b[1,1]):
 > E_r:=0.5*(((B*r^2-B*A)/r^2)-1):
 > E_theta:=0.5*((B*r^2/(r^2-A))-1):
 > E_z:=0.5*((1/B^2)-1):
 > H:
 > p:=subs(r=sqrt(B*(R_o)^2+A),H):
 > x0:=simplify((sigma_r-sigma_theta)/r):
 > y0:=simplify(sigma_z*r):
 > x1:=int(x0,r):
 > y1:=2*Pi*int(y0,r):
 > Digits:=50:
 > p_i:=1.858e3:
 > p_o:=0:
 > R_i:=1:
 > R_o:=10:
 > a_11:=165.857:
 > a_22:=47.028:
 > a_33:=145.448:
 > a_12:=46.747:
 > a_13:=0.799:
 > a_23:=14.587:
 > c:=0.0004e6:
 > F_a:=0:
 > x2:=subs(r=sqrt(B*R^2+A),x1):
 > y2:=subs(r=sqrt(B*R^2+A),y1):
 > eq1:=subs(R=R_o,x2)-subs(R=R_i,x2):
 > eq2:=subs(R=R_o,y2)-subs(R=R_i,y2):
 > Eq1:=simplify(eq1):
 > Eq2:=simplify(eq2):
 > solve({Eq1=p_o-p_i,Eq2=F_a},{A,B});
 >
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## Lorentz tansformation leaves Minkowski metric inv...

Hello everybody

I would like to check, with Spacetime Tensors computation , if  a transfomation is a Lorentz transformation , i.e that leavs Minkosky metric invariant

For esample a boost  or axis rotation transformation

Some could help me ? ( Maple 2016)

Thank's a lot

## Any comment, idea or innovation to calculate this ...

Any comment, idea or innovation to calculate this parametric integral?

Note M, II, JJ are arbitrary positive integers (0<M, II, JJ<11).

F must be a function of Pm at the final!

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## Don't know where the error is from...

Good day everyone,

I have been having problems with a system of PDE solution using `numeric`.

It's giving me the error code "Error, (in pdsolve/numeric/par_hyp) input system is too far from a 'standard' form (see ?pdsolve,numeric for more detail)" and I have checked to the best of my ability for the error but could not see anything.

The code is attached below.

Please, anyone with useful information should help. Thanks

Numeric.mw

## Solve a system of nonlinear algebraic equations...

How can these eight equations q[0]...q[7] be solved for the eight unknowns a1[0]...a1[7] and with the lowest CPU time

11.mw

## Transplots not working for PDE...

Good day everyone,

I am trying to rotate the plots of pde solution using transplot, but it is giving me errors. Anyone with better suggestions should help. The code is attached below. Thanks

Transplot_not_working.mw

## use union, intersection and minus A and B...

I want to use union, intersection and minus to find. Help me

## What is the convenient way to export a large symbo...

What is the best and accurate way to export a large symbolic matrix (200*300) from Maple to Matlab? The Marix have a lot of variables, symbols and operators such as diiff, int, ....

Here is a simple example:

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## Why this procedure does not work to get the numeri...

Where is the problem within this procedure which I can not get the numerical values of V[1] , V[2], ...

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 > test:=proc(n)   local s,t,M,V;   s:=1:   for t from 1 to n do     M:=A+A^(-1);     V[s]:=(M.B):     s:=s+1:   end do;   V; end proc:
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## Where is the problem in my loop which increases th...

In part of my program, I have a loop that the iterative calculations are performed there. During running the program when it comes to the loop the memory usage become full in a short period of time and I face the memory shortage. Since my program is so long and huge, I only can show the loop part of it here, you may look at where is the problem of high memory usage in loop and how to deal with it. Any comment will be appreciated.

I again note that, this segment can not be run independently since it is a part of big program. I put it just to see and mmake comment if any.

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External force

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Loop

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## Rotate graph on x and y components...

Good day everyone,

Can I plot the graph of the sheet attached below such that x will be on the vertical component and y will be on the horizontal component? Can this be done on Maple? Anyone with useful information should please help.

plot_graph.mw

## Why extracting a n*1 matrix from n*m matrix gives...

I am trying to do the following computation. I  extracted n*1 matrix from n*n matrix which unbelievably gives vector?

How I can do the following multiplication without using convert command? Or how to extract n*1 matrix (not vector) from n*n matrix without using convert?

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## How can the multiplication of two functions be con...

If i have p := 8*T(x, 7)*T(x, 2)+4*T(x, 5)*T(x, 1)+6*T(x, 3)*T(x, 3)+7*T(x, 1)*T(x, 4)

I want to convert the the multiplication functions like T(x, 7)*T(x, 2) into summation T(x, 7)+T(x, 2)