integral competition HP50g vs. DM42

[Albert Chan]

(08-19-2020 07:28 PM)peacecalc Wrote:  S(3.9) = 0.4752 and C(3.9) = 0.4223;

Using complex numbers, we can do both C(x), S(x) at the same time

XCas> F := int(exp(i*pi/2*x*x),x)     → erf(sqrt(pi)/2 * x * (1-i)) / (1-i)

Since erf(0)=0, we have F(x) = C(x) + i * S(x)

XCas> subst(F, x=3.9)                     → 0.422332710261 + 0.475202402351*i