8. Show that r(t) = a cost+bsint is an ellipse even if a and b are not orthogonal. How do you find the major and minor radii vectors? [Hint: find to such that r. r = 0 and define a' = r(to) and b' = r(to). Express a, b and r(t) in terms of a', b'.]

30. Find an equation of the plane that contains the points (-2, 1, 4) and (0, 3, 1) and contains a line parallel to the vector 2i - 4j + 6k.

Pls help ASAP