The curve defined implicitly by x4−y=0 has a critical point at (0,0). At that point dxdy=0 and dx2d2y=0. Which statement best describes (0,0)?
a) (0,0) is a saddle point because the second derivative is zero.
b) (0,0) is a local minimum even though the second derivative test is inconclusive.
c) No conclusion can be drawn about (0,0); additional analysis cannot classify it.
d) (0,0) is a local maximum because the second derivative is zero.