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標題:

F.5 MATHS

發問:

F.5 MATHS................................... For each of the following pairs of straight line L1 and L2, (a)determine whether L1 and L2 are parallel, (b)find the equation of the locus of a point which is equidistant from L1 and L2. L1:x-y+2=0,L2:2x-2y-5=0

最佳解答:

(a) Slope of L1 = 1 Slope of L2 = 2/2 = 1 So L1 and L2 are parallel. (b) 圖片參考：http://imgcld.yimg.com/8/n/HA00430051/o/701011210068313873413330.jpg 2010-11-21 14:38:39 補充： Sorry,for(b),the answer should be: 丨(a - b + 2)/root(1+1)丨=丨(2a - 2b - 5)/root(2^2+2^2)丨 丨2a - 2b + 4丨=丨2a - 2b - 5丨 2a - 2b + 4 = 2a - 2b - 5 or 2a - 2b + 4 = -2a + 2b + 5 4 = -5 (rej.) or 4a - 4b - 1 = 0 So the required locus is 4x - 4y - 1 = 0

其他解答:B5117735D6B60D95