i. (From la and b.) Show how to use the graph of the skydiver's height against time to estimate the velocity of the skydiver at t = 25 and t = 75. ii. (From 1d.) Show and explain how to use points from the graph to determine the values of a, m, and b in the piecewise function: at 2 if 0 30 iii. (From le.) Use the function s(t) and the difference quotient to compute an approximate value for v(25). Compare this approximation to what you found in part a. iv. (From c. ) Sketch a graph (on well labeled axes) of the velocity of the skydiver over time. There should be a jump at t = 30. Explain why this happens