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2.9.6  Complementary error function: erfc

erfc takes as argument a number a.
erfc returns the value of the complementary error function at x=a, this function is defined by :

erfc(x)=
2
π
+∞


x
et2dt=1−erf(x

Hence erfc(0)=1, since :

+∞


0
et2dt=
π
2
 

Input :

erfc(1)

Output :

0.15729920705

Input :

1- erfc(1/(sqrt(2)))*1/2

Output :

0.841344746069

Remark
The relation between erfc and normal_cdf is :

normal_cdf(x)=1−
1
2
erfc (
x
2

Verification :
normal_cdf(1)=0.841344746069


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