MATLAB: Problem with integration need help

integration

Hi guys,

The next code is to solve an integration. The code will keep running without show any result. Please, need your help if you know the reason.

The code is;

syms T1 T2 r1 r2 r w m k Tb
clc
b=(-4*m*w^2*r1^4)/(k*(r2^2-r1^2));
c1=((T2-T1)+(b*r2^2/4)*(((r2/r1)^2)-1))/(log(r2/r1));
c2=T1-((b*r2^4)/(4*r1^2))-(((T2-T1)+(b*r2^2/4)*(((r2/r1)^2)-1))/(log(r2/r1)))*log(r1);
Tb=(int((((c1*r/2)+(c2/r))*((b*r2^4/4*r^2)+(c1*log(r)+c2))*r),r,r1,r2))/....
   (int(((((-2*w*r1^2)/(r2^2-r1^2))*(r/2))+(((w*r1^2*r2^2)/(r2^2-r1^2))*(1/r)))*r,r,r1,r2));

Best Answer

Try breaking Tb up into two pieces, numerator and denominator, so that you can figure out which of the two integrations is giving the problem.

In my tests with a different mathematics system, the integrations were fast.

Related Solutions

MATLAB: Solve symbol four equations for c1 c2 c3 c4

Thanks, I solve it,

clc
clear
syms a b x y c1 c2 c3 c4 T1 T2 T3 T4  
T=c1+c2*x+c3*y+c4*x*y;
%%
r1=c1+c2*a+c3*b+c4*a*b-T1;
r2=c1-c2*a+c3*b-c4*a*b-T2;
r3=c1-c2*a-c3*b+c4*a*b-T3;
r4=c1+c2*a-c3*b-c4*a*b-T4;
%%Find C1 and C4
p13=r1+r3;
p24=r2+r4;
n1=solve(p13==0,c1);
n2=solve(p24==0,c1);
C4=solve(n1==n2,c4)
w1=solve(p13==0,c4);
w2=solve(p24==0,c4);
C1=solve(w1==w2,c1)
r1=subs(r1,c1,C1);
r1=subs(r1,c4,C4);
r2=subs(r2,c1,C1);
r2=subs(r2,c4,C4);
r3=subs(r3,c1,C1);
r3=subs(r3,c4,C4);
r4=subs(r4,c1,C1);
r4=subs(r4,c4,C4);
%%Find C3
q12=r1+r2;
q34=r3+r4;
C3=solve(q12==0,c3)
r1=subs(r1,c3,C3);
r2=subs(r2,c3,C3);
r3=subs(r3,c3,C3);
r4=subs(r4,c3,C3);
%% find C2
C2=solve(r1==0,c2)
r1=subs(r1,c2,C2);
r2=subs(r2,c2,C2);
r3=subs(r3,c2,C2);
r4=subs(r4,c2,C2);
C1
C2
C3
C4

MATLAB: Newton-raphson for 12 equations

To solve this set of equations, I'd use the optimization toolbox function fsolve. Define your set of equations in a function (for simplification, I skip Beta and Gamma):

function w=test(x,B,Alpha)
w=B*x-Alpha./(1-x.^4);

and solve it by

 fsolve(@(x) test(x,B,Alpha),ones(size(B,2),1))

Of course, B and Alpha must be defined beforehand. Does it work?

In case you cannot use the optimization toolbox, you'll find couple of files at the file exchange indexed with "Newton Raphson". I didn't read through them, but most likely, you'll find one which is supporting the same syntax.

Best regards,

Michael

Best Answer

Related Solutions

MATLAB: Solve symbol four equations for c1 c2 c3 c4

MATLAB: Newton-raphson for 12 equations

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