極大 left parenthesis, StartFraction, pi Over 4 , EndFraction , "f" left parenthesis, StartFraction, pi Over 4 , EndFraction , right parenthesis , right parenthesisπ4,fπ4
接点 left parenthesis, StartFraction, pi Over 2 , EndFraction , "f" left parenthesis, StartFraction, pi Over 2 , EndFraction , right parenthesis , right parenthesisπ2,fπ2