To find the instantaneous rate of change, we need to find the derivative of #1/x#. Putting in values of #x# will give us the gradient of the tangent at that point. This is different from the average rate of change, which is the gradient of the secant line that joins #2# points.
So the instantaneous rate of change is given by #f'(a)#, and the average rate of change on an interval #[a,b]# is given by
#((f(b))-(f(a)))/(b-a)#
#1/x=x^-1#
Using the power rule:
#dy/dx(x^n)=nx^(n-1)#
#dy/dx(x^-1)=-x^(-2)=-1/x^2#
#:.#
#x_0=2#
#f'(x_0)=-1/(2)^2=color(blue)(-1/4)#
#x_1=3#
#f'(x_1)=-1/(3)^2=color(blue)(-1/9)#
Instantaneous Rate of Change:
Average Rate of Change: