/ -x\ 3*acos\E /
-x 3*e -------------- ___________ / -2*x \/ 1 - e
/ -2*x \ | e | -x -3*|1 + ---------|*e | -2*x| \ 1 - e / ---------------------- ___________ / -2*x \/ 1 - e
/ -4*x -2*x \ | 3*e 4*e | -x 3*|1 + ------------ + ---------|*e | 2 -2*x| | / -2*x\ 1 - e | \ \1 - e / / ------------------------------------ ___________ / -2*x \/ 1 - e