標題:

F5 Maths circle

發問:

A straight line cuts the circle C1: (x-4)^2+(y-3)^2=64 at P (-4, 3) and Q(4, -5). Find the equation of circle C2 passing through P, Q and the centre of C1. The answer is x^2+y^2+2y-31=0 Show me the steps please. 更新: Why D = 0 ???

最佳解答:

Centre of C1: (4,3). We can set C2 x^2 + y^2 + Dx + Ey + F = 0 Sub. P (-4, 3) and Q(4, -5) and M(4, 3) 25 - 4D + 3E + F = 0...(1) 41 + 4D - 5E + F = 0...(2) 25 + 4D + 3E + F = 0...(3) (1) (3)=> D = 0 Then 25 + 3E + F = 0...(1) 41 - 5E + F = 0...(2) => E = 2, F = -31 So, C2: x^2 + y^2 + 2y - 31 = 0 2011-01-27 17:26:02 補充： (3) - (1) 8D = 0 D = 0

其他解答:

aa.jpg

 

此文章來自奇摩知識+如有不便請留言告知

arrow
arrow
    文章標籤
    我想 文章 奇摩
    全站熱搜
    創作者介紹
    創作者 rlz87tm45t 的頭像
    rlz87tm45t

    rlz87tm45t的部落格

    rlz87tm45t 發表在 痞客邦 留言(0) 人氣()

    E-mail轉寄