If a surface is defined by g(x,y,z)=x2+y2+z2=9g(x, y, z) = x^2 + y^2 + z^2 = 9g(x,y,z)=x2+y2+z2=9, find the normal vector at (1,2,2)(1, 2, 2)(1,2,2).
⟨1,2,2⟩\langle 1, 2, 2 \rangle⟨1,2,2⟩
⟨1/3,2/3,2/3⟩\langle 1/3, 2/3, 2/3 \rangle⟨1/3,2/3,2/3⟩
⟨2,4,4⟩\langle 2, 4, 4 \rangle⟨2,4,4⟩
⟨2,2,1⟩\langle 2, 2, 1 \rangle⟨2,2,1⟩