/ ___\ |\/ x | asin|-----| \ 2 /
asin(sqrt(x)/2)
1 ------------------- _______ ___ / x 4*\/ x * / 1 - - \/ 4
1 4 ----- - - x x 1 - - 4 -------------------- _______ ___ / x 32*\/ x * / 1 - - \/ 4
3 48 8 -------- + -- - --------- 2 2 / x\ / x\ x x*|1 - -| |1 - -| \ 4/ \ 4/ ------------------------- _______ ___ / x 256*\/ x * / 1 - - \/ 4