Matlab not computing integral

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Brandon Peter
Brandon Peter el 13 de Sept. de 2018
Respondida: Walter Roberson el 14 de Sept. de 2018
I am new to Matlab and cannot figure out why Matlab will not calculate this integral. Any help would be greatly appreciated. Thanks!
clc;
%Symbolic Variables
syms lambda_x x x_prime y y_prime pi k
%Constants
k = 10;
x = 5;
y = 6;
x_prime = -1;
y_prime = 2;
g1 = exp(1i*lambda_x*(x-x_prime))*exp(-1i*abs(y-y_prime)*sqrt((k^2)-(lambda_x^2)));
g2 = sqrt((k^2)-(lambda_x^2));
g3 = g1/g2;
g3integral = int(g3,lambda_x,-inf,inf, 'PrincipalValue', true);
pretty(g3integral)
  4 comentarios
Jan
Jan el 14 de Sept. de 2018
What about integrating it numerically and not symbolically?
Brandon Peter
Brandon Peter el 14 de Sept. de 2018
How would you go about doing that?

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Respuestas (1)

Walter Roberson
Walter Roberson el 14 de Sept. de 2018
Numerically it is undefined because the denominator passes through 0, giving a division by 0.
The cauchy principle value does not appear to exist. Take the limit of g3 as lambda_x approaches -infinity or +infinity and you will see it being infinite. Take the limit as lambda_x approaches -10 or +10 and you will see complex infinities with different sign on the two sides of the discontinuity.

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