Mathematica Asked by shahrukh on March 21, 2021
I am trying to numerically integrate the following double integral in MATHEMATICA. This question has also been asked at Wolfram Community
where $Im$ is the imaginary part of the expression, $i$ is the imaginary number, $x$ and $y$ are variables while $a, b, c$ and $Q$ are constants greater than 0.
Here is my attempt to solve this.
a = 3
b = 0.0137
c = 0.0023
Q = 6
NIntegrate[
Im[Exp[-I x c + b (I x y/(y^a - I x))]]/x, {x, 0, ∞}, {y, 0, Q},
AccuracyGoal -> 10]
Is this the correct way of applying numerical integration with more than one variable? I am getting an error when I run this expression which reads as
evaluated to non-numerical values for all sampling points in the region with boundaries {{[Infinity], 0.},{0, 6}}.
Can anyone please guide me to correct the implementation of the expression given above.
ComplexExpand the functions and integrate separately.(Because I am in a hurry, i don't show intermediate results)
ceRe = ComplexExpand[Re[(I x y)/(y^3 - I x)],
TargetFunctions -> {Re, Im}]
ceIm = ComplexExpand[Im[(I x y)/(y^3 - I x)],
TargetFunctions -> {Re, Im}]
intRe[x_] = Integrate[ceRe, {y, 0, 6}, Assumptions -> x > 0]
intIm[x_] = Integrate[ceIm, {y, 0, 6}, Assumptions -> x > 0]
ii[x_] = ComplexExpand[Im[Exp[-I x c + b*(intRe[x] + I intIm[x])]]/x,
TargetFunctions -> {Re, Im}] /. {b -> 137/10000, c -> 23/10000} //
Simplify[#, x > 0] &
Plot[ii[x], {x, 0, 10000}]
nint = NIntegrate[ii[x], {x, 0, [Infinity]}, MaxRecursion -> 50]
(* -0.989098 *)
Correct answer by Akku14 on March 21, 2021
Get help from others!
Recent Questions
Recent Answers
© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP