[x1, x2, x3, x4, x5, x6, x7, x8]
x1^2 - x2^2 - x3^2 - x4^2 - x5^2 - x6^2 - x7^2 - x8^2;
2*x1*x2;
2*x1*x3;
2*x1*x4;
2*x1*x5;
2*x1*x6;
2*x1*x7;
2*x1*x8;
[[-0.01, 10], [-0.01, 10], [-0.01, 10], [-0.01, 10], [-0.01, 10], [-0.01, 10], [-0.01, 10], [-0.01, 10]]
# This function has a unique zero f(0)=0 of index two