Answer
The required inequality is: $z>=0$, for the equation of the sphere: $x^{2}+y^{2}+z^{2}=4$
Work Step by Step
For a radius R and sphere with centre at the origin, the equation is: $x^{2}+y^{2}+z^{2}=R^{2}$.
Here, R=2
Thus, $x^{2}+y^{2}+z^{2}=4$
For the upper hemisphere, imagine a sphere in the x,y,z coordinates. The upper hemisphere lies in the positive z axes. Thus, the inequality is $z>=0$
