State two points on the graph of y=sinx that will give an average rate of change of 0?
well wherever the derivative is zero, the INSTANTANEOUS rate of change is zero.
That means whenever the cos x = 0
which is at pi/2 , 3pi/2 etc so those do work but.....
HOWEVER the average change is zero between any two points a period apart
in other words between x = 0 and x = 2 pi
or x = 1 and x = 1+2pi
or 0 and 600 pi
or whatever