ƚ  z J .   &@ @ & MathTypeSymbolQ ؟ww w f-2 "Ry2 Ry2 Ry2 =y2 +y2 -y2 =y2 -y2 -y2 ry2 ":y2 :y2 :y2 =y2 +y2 D-y2 0 y2 =y2 +yTimes New Roman؟ww w f-2 20 2  e2 122 242 2  e2 202 122 242 2  2 202 122 422 42 2   2  2 F5 2 "3 Times New Roman؟ww w f-2 y 2  x 2 y 2  x 2 ty 2 x 2 y 2  x & "System f !-