Touba M. answered 03/24/20
B.S. in Pure Math with 20+ Years Teaching/Tutoring Experience
Hi.
x2 + y2 + z2 = 1 .represents a sphere that center is origin and radius is 1
x2 + y2 + z2 ≤ 1 . represents all points inside and on the above sphere
so the min is center and max is all points are on the sphere.
I hope it is useful,
Minoo