- #1
trmcclain
- 14
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Homework Statement
I'm working with a particularly malicious mass model function given as:
λ^n*exp(-x^2)*(λ+x)^-n, λ=constant, n=constant (1.8 for those who care)
The first round of integration by parts using
u=(λ+x)^-n, du=-n(λ+x)^(-n-1)dx
dv=exp(-x^2), v=sqrt(pi)/2*erf(x)
Gives me:
(λ+x)^-n*[sqrt(pi)/2]*erf(x) + [n*sqrt(pi)/2]*∫erf(x)*(λ+x)^(-n-1)dx
Now I know for any given value of x, the erf(x) has a known value. C++ even has a function for it.
My question is, is it good math to utilize the fact that erf(x) for any finite value is known and constant to pull it out of the integral? Or do I need to utilize a different integration technique to solve this equation?
For anyone interested, I am trying to use this equation as a probability density model to randomly scatter points.