Problem #8. a) Find the unit tangent vector to the curve at the specified value of the parameter: (5%) 70) = 7(t2 cos 3t? + W sin 3tf) + tk, where t = 99. b) Find the lirnit, if it exist: (5%) _ .> Slut3 > 11m (62% +] +e'6'k >. I c) Find 70') and |7'(t)| for the trajectory: (5%) ?(t) = (t sin I, 1 cost, I)