ƚ  ] m .   &E & MathType- Times New Roman؟ww whff-2 g ny2 Bny2 nyTimes New Roman؟ww whff-2 )by2 ,ay2  by2 aySymbol ؟ww whff-2 =y2 y2 :y2 y2 .y2 :.y2 .y & "Systemfhff !-