The equation of the tangent plane to the ellipsoid
x^2/a^2 + y^2/b^2 + z^2/c^2 = 1
at the point
(x0, y0, z0)
can be written as
xx0/a^2 + yy0/b^2 + zz0/c^2 = 1
Find the equation of the tangent plane to the
hyperboloid
x^2/a^2 + y^2/b^2 - z^2/c^2 = 1
at
(x0, y0, z0)
and express it in a form similar to the one for the
ellipsoid.