Pierre, the mountain climbing ant, moves along the x-axis so that at time t its position is given by x(t) = 2cos(π/2 t^2).

For values of t in the interval [-1,1]
(a)Find an expression for the velocity of the ant at any given time t.
(b) Find an expression for the acceleration at any given time t.
(c)Determine the values of t for which the ant is moving to the right.
Justify your answer.
(d) Determine the values of t for which the ant changes direction.
Justify your answers.