can I find a solution for this integral?

1 view (last 30 days)
r=sqrt(x.^2+y.^2);
theta=atan2(y,x);
ab1=1;xi=2;n=10;
h=@(t) (t.*(exp(-xi.*(r.*cos(theta)+ab1))-exp(-t.*(r.*cos(theta)+ab1))).*((-1).^(n-1).*exp(-ab1.*t)./factorial( n )).*t.*besselj(1,t.*r.*sin(theta)));
integral(h, 0, inf)
  7 Comments
Shreen El-Sapa
Shreen El-Sapa on 3 Aug 2021
i will use this notation and recalculate it.
thanks so much
Shreen El-Sapa
Shreen El-Sapa on 4 Aug 2021
in this case it excuted but i wanted to use the values in the lines 17 and 18 it failed
syms t real
a = 1 ; %RADIUS
L=.4;
c =-a/L;
b =a/L;
m =a*200; % NUMBER OF INTERVALS
[x,y]=meshgrid([c:(b-c)/m:b],[c:(b-c)/m:b]');
[I J]=find(sqrt(x.^2+y.^2)<(a-.1));
if ~isempty(I)
x(I,J) = 0;
y(I,J) = 0;
end
r = sqrt(x.^2+y.^2);
theta = atan2(y,x);
ab1=1; xi=2; n=10; k=2;
% I want to use the following green lines instead of above values of ab1=1; xi=2; n=10; k=2;
%chi=1;alpha=1;ab1=1;
%k=sqrt(chi.^2+alpha.^2);xi=sqrt(t.^2+k.^2);
h=@(t)(t-xi).^(-1).* (t.*(exp(-xi.*(r.*cos(theta)+ab1))-exp(-t.*(r.*cos(theta)+ab1))).*(((-1).^(n-1).*t.^(n-1).*exp(-ab1.*t)./factorial( n ))+((-1).^(n).*sqrt(pi.*k./2./t.^2).*exp(-ab1.*xi).*gegenbauerC(n,-1./2, xi./k))).*t.*besselj(1,t.*r.*sin(theta)));
hint = integral(h, 0, inf, 'ArrayValued', true)

Sign in to comment.

Accepted Answer

Dave B
Dave B on 3 Aug 2021
When I run this code with scalar x,y it works fine:
x=2;y=2;
r=sqrt(x.^2+y.^2);
theta=atan2(y,x);
ab1=1;xi=2;n=10;
h=@(t) (t.*(exp(-xi.*(r.*cos(theta)+ab1))-exp(-t.*(r.*cos(theta)+ab1))).*((-1).^(n-1).*exp(-ab1.*t)./factorial( n )).*t.*besselj(1,t.*r.*sin(theta)));
integral(h, 0, inf)
When I run this code with vector x and y it fails:
x=[1 2];y=[1 2];
r=sqrt(x.^2+y.^2);
theta=atan2(y,x);
ab1=1;xi=2;n=10;
h=@(t) (t.*(exp(-xi.*(r.*cos(theta)+ab1))-exp(-t.*(r.*cos(theta)+ab1))).*((-1).^(n-1).*exp(-ab1.*t)./factorial( n )).*t.*besselj(1,t.*r.*sin(theta)));
integral(h, 0, inf)
"For scalar-valued problems, the function y = fun(x) must accept a vector argument, x, and return a vector result, y. This generally means that fun must use array operators instead of matrix operators. For example, use .* (times) rather than * (mtimes). If you set the 'ArrayValued' option to true, then fun must accept a scalar and return an array of fixed size."
Here, your function accepts a scalar argument (t) and returns an array:
size(h(0)) == size(r); % for all scalar h, for all size(r) (at least that I tested)
"Set this flag to true or 1 to indicate that fun is a function that accepts a scalar input and returns a vector, matrix, or N-D array output."
Thus, if x and y are arrays, do you want the following?
integral(h, 0, inf, 'ArrayValued', true)
  2 Comments
Shreen El-Sapa
Shreen El-Sapa on 4 Aug 2021
in this case it excuted but i wanted to use the values in the lines 17 and 18 it failed
syms t real
a = 1 ; %RADIUS
L=.4;
c =-a/L;
b =a/L;
m =a*200; % NUMBER OF INTERVALS
[x,y]=meshgrid([c:(b-c)/m:b],[c:(b-c)/m:b]');
[I J]=find(sqrt(x.^2+y.^2)<(a-.1));
if ~isempty(I)
x(I,J) = 0;
y(I,J) = 0;
end
r = sqrt(x.^2+y.^2);
theta = atan2(y,x);
ab1=1; xi=2; n=10; k=2;
% I want to use the following green lines instead of above values of ab1=1; xi=2; n=10; k=2;
%chi=1;alpha=1;ab1=1;
%k=sqrt(chi.^2+alpha.^2);xi=sqrt(t.^2+k.^2);
h=@(t)(t-xi).^(-1).* (t.*(exp(-xi.*(r.*cos(theta)+ab1))-exp(-t.*(r.*cos(theta)+ab1))).*(((-1).^(n-1).*t.^(n-1).*exp(-ab1.*t)./factorial( n ))+((-1).^(n).*sqrt(pi.*k./2./t.^2).*exp(-ab1.*xi).*gegenbauerC(n,-1./2, xi./k))).*t.*besselj(1,t.*r.*sin(theta)));
hint = integral(h, 0, inf, 'ArrayValued', true)

Sign in to comment.

More Answers (0)

Categories

Find more on Get Started with Symbolic Math Toolbox in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!