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Different results in symbol integration

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ConvexHull
ConvexHull 2020-7-19
编辑： ConvexHull 2020-7-19
Dear all,
whats going wrong here? I only changed the order of the dependend variables from (x1,x2,x3,x4) to (x2,x1,x3,x4).
syms x1 x2 x3 x4
Variant 1:
f(x1,x2,x3,x4)=exp(-x1^2)*exp(-x2^2)*exp(-x3^2)*exp(-x4^2)*x1;
F(x1,x2,x3,x4)=int(int(int(int(int(f,x1),x2),x3),x4));
Result: F(1,1,1,1)
= -(pi^2*erf(x1)*erf(x2)*erf(x3)*erf(x4))/32
= -0.1555
Variant 2:
f(x2,x1,x3,x4)=exp(-x1^2)*exp(-x2^2)*exp(-x3^2)*exp(-x4^2)*x1
F(x2,x1,x3,x4)=int(int(int(int(int(f,x1),x2),x3),x4));
Result: F(1,1,1,1)
= -(pi^(3/2)*exp(-x1^2)*erf(x3)*erf(x4)*(exp(-x2^2)/pi^(1/2) + x2*erf(x2)))/16
= -0.0955
Regards
System:
Linux Ubuntu 18.04
MATLAB R2018a

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采纳的回答

ConvexHull
ConvexHull 2020-7-19
Have found my bug. I have integrated five times.
Thanks anyway!

更多回答（1 个）

madhan ravi
madhan ravi 2020-7-19
Called int() 5 times instead of 4.

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