z = (3.125,4.25)
 has real part = 3.125
 and imaginary part = 4.25i
z has complex conjugate = (3.125,-4.25)
AGM((3.125,4.25),(1,0)) = (2.07831617217326684,1.56336158990659582)

AGM((1,1),(2,1)) = (1.471349362864653566,1.02005412633766002)

Enter Integer coefficients of a (monic) cubic:The 1 root(s) are:
[ -1 ]
Enter a real or complex: Main cube root = (1.628937145922175875,0.5201745023045458395)
whose cube is    (3,4)
Next cube root = (-1.26495290635775166,1.1506136983844505)
whose cube is    (3,4)
Next cube root = (-0.3639842395644242155,-1.670788200688996339)
whose cube is    (3,4)
Enter real coefficients a b c d e of a quartic:Quartic [1,2,3,4,5] has roots:
(-1.287815479557647989,-0.8578967583284902864)
(-1.287815479557647989,0.8578967583284902864)
(0.2878154795576479889,1.416093080171907939)
(0.2878154795576479889,-1.416093080171907939)