In: Math
for stationary point we set f"(x)=0
=> x=0
At x=0 f(x)=f(0)=0-0=0
Therefore stationary point is (0,0)
For concave upward f"(x)>0
=> x^(1/3)<0
f(x) is concave up on
for concave downward f"(x)<0
f is concave down on
The graph looks like