Hi,

I am looking to do some line fitting of Lorentzian/Cauchy functions to a type of chromatogram. It is working fine, but I need an analytical expression to the area of the curve. The function is given as:

f(x) = I*y^2/((x-x0)^2+y^2)

where I,y,x0 are constants. Using Wolfram|Alpha to integrate, I get the following: F(x) = Iyatan((x-x0)/y) + C

The integral should be taken from -inf to inf. As atan approaches a constant value, the integral equals 0. Where am I going wrong in this? Is the integral undefined for this problem, or are my math skills just lacking? The integral should be dependent of I and y, but not x0.