Question

b.) Based on the values in the table, what is the smallest number of instances at which the acceleration of the plane could equal zero on the open interval 0< t < 40 ? Justify your answer
c.) The function f, defined by f(t) = 6 + cos(t/10) + 3 sin(7t/40) , is used to model the velocity of the plane, in miles per minute, for 0 < or equal to t < or equal to 40. According to this model, what is the acceleration of the plane at t=23 ? Indicate units of measure.