| 释义 | 
		Gaussian IntegralThe Gaussian integral, also called the Probability Integral, is the integral of the 1-D Gaussian over .  It can be computed using the trick of combining two 1-D Gaussians
   and switching to Polar Coordinates,
  However, a simple proof can also be given which does not require transformation to Polar Coordinates (Nicholas andYates 1950).
 
 The integral from 0 to a finite upper limit   can be given by theContinued Fraction
    | (3) |  
 
 
 The general class of integrals of the form
    | (4) |  
  can be solved analytically by setting
  Then
  For  , this is just the usual Gaussian integral, so 
   | (9) |  
  For  , the integrand is integrable by quadrature,
   | (10) |  
  To compute   for  , use the identity
  For   Even,
  so 
   | (13) |  
  If   is Odd, then
  so
   | (15) |  
  The solution is therefore
   | (16) |  
  The first few values are therefore
   |   |   | (17) |    |   |   | (18) |    |   |   | (19) |    |   |   | (20) |    |   |   | (21) |    |   |   | (22) |    |   |   | (23) |  
 
  A related, often useful integral is
 
   | (24) |  
  which is simply given by
   | (25) |  
  References
 Nicholas, C. B. and Yates, R. C.  ``The Probability Integral.''  Amer. Math. Monthly 57, 412-413, 1950.  |