標題: 請教一題數.... [打印本頁] 作者: liangg 時間: 1/9/2008 06:51 AM 標題: 請教一題數.... 1.Let x and y be two variables such that xy" is a constaant . When x is doubled, what is the % change of y?? (" = 2 次方)作者: sapphire 時間: 1/9/2008 08:39 AM xy^2 = k where k is a constant
When x is doubled, 2x (y / √2)^2 = k
So y becomes (1 / √2) y, % change = 70.7 %作者: liangg 時間: 2/9/2008 10:14 PM 我明la!! 好多謝你的解答!!!