Hyperboloids of 1 Sheet Whose Axis is the z-axis

This is the equation of a hyperboloid of 1 sheet whose axis is the z-axis

> hyperz:=x^2/a^2+y^2/b^2-z^2/c^2=1;

Let's check it out for a=1, b=2, and c=3

> hyperz1:=subs({a=1,b=2,c=3},hyperz);

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Plot of the hyperboloid "hyperz1"