y=x+m與x²;/4 +y²;/3 =1聯立,消x得7y²;/12 -my/2 +m²;/4 -1=0, 由韋達定理得y1+y2=6m/7,y1*y2=(3m²;-12)/7 . ... 當m²;=7/2時,S²;△AOBmax=3,S△AOB=根號3.
確定! 回上一頁