FNCireturns the value of the cosine integral ofx, Ci(x). Ci(x) is defined by the relation
whereγis Euler's number;γ= 0.57721566490153...
The real version of Ci(x) is only defined for positive values ofx. Large positive values ofxmay produce results greater than MAXREAL, the largest value representable.
Ci(x)
Errors
FNCicauses an HTBasic error if its argument is not of type REAL. It also causes an error if the value ofxis negative or zero or if Ci(x) would be greater than MAXREAL.