quot;quot;Among all planes that are tangent to the surface xy^2z^2=1, find the ones that are farthest from the originquot; So for this problem, I

""Among all planes that are tangent to the surface xy^2z^2=1, find the ones that are farthest from the origin"So for this problem, I need to find the tangent plane that is farthest from the origin.I know my contraint for lagrange multipliers is the equation of the surface. But I don't know what my function f is to use. What is the other equation to use for lagrange multipliers. "