Find d²y dx2¹ parametric equations: X = Y = d²y dx² as a function of t, for the given the 3 - 2 cos(t) 7+cos³ (t) (a) Find dy dx expressed as a function of t for the given the parametric equations: cos⁹ (t) X = y 2 sin²(t) dy dx (b) Find d²y dx² expressed as a function of t. d²y dx² # dy (c) Except for at the points where is undefined, is dx the curve concave up or concave down? (Enter 'up' or 'down').