Integral "int" function not evaluating
4 次查看(过去 30 天)
显示 更早的评论
Why is the "int" function not evaluating my integral? The "r" variable still has the "int" in it.
clear
clc
theta_s = 0:0.5:pi/2;
syms theta_v phi
for i = 1:length(theta_s)
integ2(i) = ((((1/(2*pi))*((pi-phi)*cos(phi) + sin(phi))*tan(theta_s(i))*tan(theta_v)-(1/pi)*(tan(theta_s(i))+tan(theta_v)+sqrt(tan(theta_v)^2 + tan(theta_s(i))^2 - 2*tan(theta_s(i))*tan(theta_v)*cos(phi)))))*cos(theta_v)*sin(theta_v));
r(i)= int((integ2(i)), theta_v, [0 pi/2]);
end
1 个评论
Walter Roberson
2022-3-3
What reason do you have to lead you to expect that there is a closed form integral?
采纳的回答
David Hill
2022-3-3
theta_s = 0:0.5:pi/2;
syms theta_v
phi=pi/6;%choose a phi or loop for various values of phi
for i = 1:length(theta_s)
integ2(i) = ((((1/(2*pi))*((pi-phi)*cos(phi) + sin(phi))*tan(theta_s(i))*tan(theta_v)-(1/pi)*(tan(theta_s(i))+tan(theta_v)+sqrt(tan(theta_v)^2 + tan(theta_s(i))^2 - 2*tan(theta_s(i))*tan(theta_v)*cos(phi)))))*cos(theta_v)*sin(theta_v));
r(i)= vpaintegral((integ2(i)), theta_v, [0 pi/2]);
end
6 个评论
David Hill
2022-3-4
Works fine.
theta_s = 0:0.5:pi/2;
syms theta_v phi
for i = 1:length(theta_s)
integ2(i) = ((((1/(2*pi))*((pi-phi)*cos(phi) + sin(phi))*tan(theta_s(i))*tan(theta_v)-(1/pi)*(tan(theta_s(i))+tan(theta_v)+sqrt(tan(theta_v)^2 + tan(theta_s(i))^2 - 2*tan(theta_s(i))*tan(theta_v)*cos(phi)))))*cos(theta_v)*sin(theta_v));
r(i)= vpaintegral(vpaintegral((integ2(i)), theta_v, [0 pi/2]),phi,[0 pi]);
end
Walter Roberson
2022-3-6
By the way, integrating first with respect to phi is faster.
At one point I saw a closed form solution for integration with respect to phi, but I was not able to reproduce that later.
更多回答(0 个)
另请参阅
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!