Let a=1,1a=1,-1 and b=0,kb=0,k. Find k so that aa and bb will be orthogonal (form a 90 degree angle). k =

The ellipse x^2/9^2 + y^2/4^2 can be drawn with parametric equations where x(t)x(t) is written in the form x(t)=rcos(t) with r = and y(t) =