Question

Samuel is investigating the rate of change of the function f(x) = cos x on the interval xE[0, 2pi]. He notices that the graph of f(x) passes through the x-axis at pi/2. He also determines the instantaneous rate of change at x = 0, pi and 2pi by inspection. Based on this information, determine an equation r(x) to predict the instantaneous rate of change of the function f(x) on the interval xE[0, 2pi] Then use your equation to calculate the exact instantaneous rate of change at x = pi/4

Answer 1

I bet f'=-sinx