Gaussian integrals and some integrals

The Basic Gaussian Integral

The function , called a Gaussian, appears everywhere in the mathematical sciences. It plays a fundamental role in probability and statistics.

The fundamental Gaussian integral in its simplest form






If follow when a is positive constant. In fact this remains true even if a is a complex number, as long as Re a > 0




For x ∈ R, the error function is defined by



The gaussian function, error function and complementary error function are frequently used in probability theory since the normalized gaussian curve represents the probability distribution with standard deviation s relative to the average of a random distribution. The error function represents the probability that the parameter of interest is within a range between -x/2and +x/2 while the complementary error function provides the probability that the parameter is outside that range

Relations and Selected Values of Error Functions

erf (∞) = 1
erf (−x) = − erf (x)
erf (0) = 0
erf (−∞) = −1