ƚ@  P u .  @ & @ & MathTypeSymbol s؟ww w f-2 ":y2 :y2 :y2 -y2 =y2 +y2 =y2 +yTimes New Roman؟ww w f-2 @ xy2 xy2 yy2 yy2 xyTimes New Roman؟ww w f-2 7y2 5y2 8y2 8y2 4y2 3y & "System f !-