Use the given equation to answer the following questions. (Enter your answers from smallest to largest.)
r = 8cos(¦È)
0 ¡Ü ¦È < ¦Ð
(a) Find the points on the given curve where the tangent line is horizontal.
theta=
theta=
(b) Find the points on the given curve where the tangent line is vertical.
theta=
theta=