I suspect 4/2 should actually be 4/3, since 4/2 = 2, while 4/3 would make V the volume of a sphere with radius r. But I'll stick with what's given:





In Mathematica, you can check this result via
D[4/2*Pi*r^3, r]
Step-by-step explanation:
2x+1x= -2+1
3x= -1
3x÷3= -1÷3
x=|-3.3333..|=3.33333.. or
