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  (c) TransEra Corp, 2021
E1
Exponential integral.
 
Loading        LOADSUB ALL FROM "EI.HTS"
or LOADSUB FROM "MATHLIB.HTS"
 
Usage                REAL X,Y
Y=FNE1(X)
 
Description                
FNE1 returns the value of the first-order exponential integral of x, E1(x). E1(x) is defined by the relation
The integration represents the value obtained by integrating in the complex plane along a path that excludes the origin and that does not cross the negative part of the real axis. The value of E1(x) is infinite at x = 0.
 
E1(x) is related to the exponential integral computed by the FNEi function, Ei(x), by the expression
E1(x)
 
Errors                
FNE1 causes an HTBasic error if its argument is not of type REAL or if the magnitude of E1(x) would be greater than MAXREAL, the largest value that can be represented.
 
See Also
Ei