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