I'm trying to model an experiment for a paper which includes an integral that should be no problem for mathematica but it refuses to integrate it. The integral I need to evaluate is as follows
G[q_, t_] := (E^(2 I Sqrt[676000000 \[Pi]^2 -q^2] (23/1000000 +
(1 - Cos[75000 t])/20000))q^3 ((8.46*^11 + 2.63*^11 I)
Sqrt[1.88*^-13 - q^2] - Sqrt[(0.16 + 0.049 I) - q^2]))/(Sqrt[
676000000 \[Pi]^2 - q^2] ((8.46*^11 + 2.63*^11 I) Sqrt[1.88*^-13
- q^2] + Sqrt[(0.15 + 0.049 I) - q^2]));
As you can see, it's a function of both q
and t
and I need to integrate it over q
while keeping t
constant as I have to integrate over t
later on in the simulation. I have no idea why it won't integrate, please help!
Supplementary Information - this is me trying to solve the problem
The function G
here is made up of two functions, rp
, and another called Phi_{PDM}
.
Phi_{PDM}
integrated over q is no problem, it's also where the t
dependence comes from, I've included here for completeness.
The problem lies with the function rp
as I cannot get mathematica to integrate this function over q
As you can see, there is a singularity at small values of q which is probably whats causing the problem and I tried to mitigate this with assuming q is real and/or is above 10 but this still does not help. Here is the code for the equations:
Phi[q_, t_] := (q^3/(Sqrt[(2*\[Pi]*13000)^2 - q^2]))*Exp[I*2*
(Sqrt[(2*\[Pi]*13000)^2 - q^2])*(23*^-6 + 50*^-6*(1 -
Cos[75000*t]))];
rp[q_] := ((8.46*^11 + 2.63*^11 I) Sqrt[1.88*^-13 - q^2] -
Sqrt[(0.16 + 0.049 I) - q^2])/((8.47*^11 + 2.63`*^11 I) Sqrt[
1.88*^-13 - q^2] + Sqrt[(0.16 + 0.049 I) - q^2])
I'm not very good at mathematica and I'm certainly not the savviest when it comes to mathematics in general so any ideas regarding this, or indeed a method of solving G
that I'm just not seeing due to me being a novice, would massively appreciate!
NIntegrate
? $\endgroup$NIntegrate
? $\endgroup$rp[q,t]
you can calculateint[t_ NumericQ]:=NIntegrate[rp[q,t],{q,0,20}]
depending ont
. $\endgroup$