ƚ`  Q 5 .  ` &  & MathType-tb  Times New Roman؟ww w f-2 | 202 nm 13 2 d100e2 n65 2 v100e2 nE102 `465Symbol$ |؟ww w f-2 `$ =52 `6=52 `5 & "Systemߗ f !-