# If f is defined by #f(x)= x^3 +2x^2 + x#, how do you find the value of x when the average rate of change of f on the interval #x=-1# to #x =2# is equal to the instantaneous rate of change on the interval from #x=-1# to #x=2#? The answer is x=0.786?

##### 1 Answer

Apr 6, 2015

Consider that the instantaneous rate of change is the derivative,