(723, #25) Reduce the equation to one of the standard forms, classify the surface and sketch it.

Solution: Rewriting the equation as we find that the surface is a hyperboloid of one sheet.

To sketch it analyze the traces. There are hyperbolas in both the xz and yz planes. For a fixed z the equation can be put in the form , which is the equation of an ellipse..

The surface has the following representation.

Maple code

by: gm