minor野(關英文事)
打錯題目?
應該係it is given that而不是 it is give that
引用第1樓牙宇於2010-11-09 22:48發表的 :
方法一:直接搵VERTEX(好煩唔想計)
方法二:
AS there is only 1 sol
therefore delta=0
.......
用Since代替As會否更好?
∵ y touches x-axis
∴△=b^2-4ac=0
<=> m=-16
At x-axis, y=0 (optional)
<=> y=-16x^2+8x-1=0
<=> (4x-1)^2=0
<=> x = 1/4 (repeated)
ps舊高中寫法,唔岩新高中的話別插我
[ saradomin在2010-11-09 23:03重新編輯此帖 ]