Let r (t) = Find a parametric equation of the line tangent to r (t) at the point (165, 405, 2.708 x(t) = 165 + 216t y(t) = z (t ) =Let r (t) = ( - 415 + 4, - 2e- , sin( Find the unit tangent vector T (t) at the point t = 0 T(0) = Find the positive value for which the vectpr t) : (Alt, 712, 91%2 5) } is perpendicular tn 1* '.(t) :i