arcsinc( 1-y ), for small y

[Albert Chan]

Redoing the Five minutes challenge with weighted e:
Note: sqrt(6 m d) / 4 = sqrt(6 m (8/3 z) / 16) = sqrt(m z)

m = 5280
z = 3/8 d = 3/8

e(min) = sqrt(m z) = 44.49719092 ~ 44.50
e(max) = sqrt((m + z) z) = 44.49877105 ~ 44.50

The nice error bound *guaranteed* 4 digits accuracy

e ~ (4 e(max) + e(min)) / 5 = 44.49845502

4 weighted e reach 10 digits accuracy !
w weighted e do even better, see next post ...