CHI _ _ _ _ _ _ _ _ _ _ _ _ operator
The Chi operator returns the Hyperbolic Cosine Integral function.
defint((cosh(t)-1)/t,t,0,x); - log(x) + psi(1) + chi(x) on rounded; Chi(0.35); - 0.44182471827
The numeric values for the operator Chi are computed via the power series representation, which limits the argument range.