運算式 3: "g" left parenthesis, "t" , right parenthesis equals StartFraction, 1 Over "T" , EndFraction Start integral from "t" minus StartFraction, "T" Over 2 , EndFraction to "t" plus StartFraction, "T" Over 2 , EndFraction , end integral, "f" left parenthesis, "s" , right parenthesis "d" "s"gt=1T∫t+T2t−T2fsds