New Trapedoizal Tail integration method

[Albert Chan]

(05-12-2021 06:05 PM)Namir Wrote:  The method samples two function values in each interval at f(x+h/2-h/3) and fx(x+h/2+h/3)

You might also try f(x+h/2 ± h/(2√3))
This is the points and weights for 2 points Gaussian quadrature.

Because 2√3 ≈ 3.464 relatively close to 3, this explained the good result you observed.