## Calculus (3rd Edition)

Parabolic cylinder; the trace is the parabola $y=3x^2$ in the $xy$-plane.
The equation $$y=3x^2$$ is the equation of a parabolic cylinder. (See equations on page 691.) The trace with the plane $z=27$ is the parabola $y=3x^2$ in the $xy$-plane.