/ ___\ / ___\ / ___\ / ___\ | 1 I*\/ 3 | | 1 I*\/ 3 | | 1 I*\/ 3 | | 1 I*\/ 3 | (c + 1)*c*(c - 1)*|c + - + -------|*|c + - - -------|*|c + - - + -------|*|c + - - - -------| \ 2 2 / \ 2 2 / \ 2 2 / \ 2 2 /
/ 2\ / 2 \ c*(1 + c)*(-1 + c)*\1 + c + c /*\1 + c - c/
/ 6\ c*\-1 + c /