運算式 4: StartFraction, pi Over 2 , EndFraction absolute value left parenthesis, mod left parenthesis, StartFraction, "x" Over 2 , EndFraction minus StartFraction, pi Over 4 , EndFraction , pi , right parenthesis minus StartFraction, pi Over 2 , EndFraction , right parenthesis minus StartFraction, pi squared Over 8 , EndFractionπ2absmodx2−π4,π−π2−π28