solutions of T^1 ...:
r: 3.44948974278317809820, r/4: 0.862372435695794524549; 4R: 5.00000000000000000000, R: 1.25000000000000000000
solutions of T^3 ...:
r: 3.96010188268995201223, r/4: 0.990025470672488003057; 4R: 7.76220315590459842426, R: 1.94055078897614960606