® Working rule for finding absolute maxima and/or absolute minima Step : Find all critical points of f in the interval, i.e., find points x where either f ′ ( x ) = or f is not differentiable. Step : Take the end points of the interval. Step : At all these points (listed in Step and ), calculate the values of f . Step : Identify the maximum and minimum values of f out of the values calculated in Step .
This maximum value will be the absolute maximum value of f and the minimum value will be the absolute minimum value of f .