Let  f(x) = x^4 -4x^3 - 18 x^2  + 77 Â
a)   a) Find all critical values of thefunction.       [10]
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b)   b) Find all intervals of increase anddecrease.      [10]
      c) Find all relative extrema.Use the second derivative test.  Â
      Label each as a relative max.or a relative min.      [10]
d)   d) Find on what interval(s) the function isconcave up and concavedown.      [10]   Â
e)   e) Find all inflection point(s), if any, of thefunction.       [10]
