[微分]請教一題微分

[nomindman ()]

 Let  g(x) =  f(x*2) , where  f  is  twice  differentiable  for  all  x ,

    f'(x) > 0  for  all  x ≠ 0 ,  and  f  is  concave  downward  on

    (－∞ , 0 ) and  concave  upward  on  ( 0 , ∞ ) .

  (1) At  what  numbers  does  g  have  an  extreme  value ?

  (2) Discuss  the concavity  of  g .


  因為沒有解答...請高手們幫我看看thx

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