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Coordinates
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最佳解答:
If the line joining P(-4,-2) and Q(q,4) is parallel to the line joining X(-1,0) and Y(-3,3), find the value of q. Sol ｑ－（－４）（－３）－（－１） －－－－－－＝－－－－－－－－－－ ４－（－２）３－０ ｑ＋４－３＋１ －－－－＝－－－－－－ ６３ 3(q+4)=－12 q+4=－4 q=－8 Twopoints A (1,0) and B(4,3) are given. Write down 3 possible sets ofcoordinates of point C such that traingle ABC is a right- angled traingle. Sol A is 90 degree set C(3,-2) ==>A(1,0),B(4,3),C(3,-2) B is 90 degree set C(3,4) ==>A(1,0),B(4,3),C(3,4) C is 90 degree set C(1,3) ==>A(1,0),B(4,3),C(1,3)
其他解答:
(因為PQ同XY係parallel..佢地gei slope 係1樣 只要知XY的slope,就知PQ的slope) slope of XY= (0-3) / (-1+3) = -3/2 slope of PQ = (-2-4) / (-4-q) = 6/q+4 slope of XY=slope of PQ -3/2 = 6/q+4 -3q-12 = 12 -3q = 24 q = -8 Let C=(x,y) 1.AB perpendicular to BC 2.BC perpendocular to AC 3.AB perpendocular to AC case1: slope of AB= 3/3 = 1 slope of BC= y-3 / x-4 slope of AB x slope of BC =-1 y-3 / x-4 = -1 y-3 = -x+4 y= -x+7 coordinate of C may be ( x, 7-x) case2: slope of BC= y-3/ x-4 slope of AC= y/ x-1 slope of BC x slope of AC = -1 y^2-3y / x^2-5x+4=-1 y^2-3y = -x^x+5x-4 x^x+y^2-5x-3y+4=0 the coordinate of C may be on the line x^x+y^2-5x-3y+4=0 case3: slope of AB= 3/3 = 1 slope of AC= y/ x-1 slope of AB x slope of AC = -1 y/ x-1= -1 y= 1-x the coordinate of C may be ( x, 1-x) 2009-05-03 20:39:03 補充： 應該係 case2: slope of BC= y-3/ x-4 slope of AC= y/ x-1 slope of BC x slope of AC = -1 y^2-3y / x^2-5x+4=-1 y^2-3y = -x^2+5x-4 x^2+y^2-5x-3y+4=0 the coordinate of C may be on the line x^2+y^2-5x-3y+4=0
Coordinates
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- Maths急需!!!@1@
- 幾何問題(本來我只想係打四個字o既題目，但係畀個sysytem強迫打多d字，好無癮，yahoo唔應該咁做)
- 行人o既英文!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!高人求救!!!!!!!!!!!!!!!!!!!@1@
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If the line joining P(-4,-2) and Q(q,4) is parallel to the line joining X(-1,0) and Y(-3,3), find the value of q. Two points A (1,0) and B(4,3) are given. Write down 3 possible sets of coordinates of point C such that traingle ABC is a right- angled traingle.最佳解答:
If the line joining P(-4,-2) and Q(q,4) is parallel to the line joining X(-1,0) and Y(-3,3), find the value of q. Sol ｑ－（－４）（－３）－（－１） －－－－－－＝－－－－－－－－－－ ４－（－２）３－０ ｑ＋４－３＋１ －－－－＝－－－－－－ ６３ 3(q+4)=－12 q+4=－4 q=－8 Twopoints A (1,0) and B(4,3) are given. Write down 3 possible sets ofcoordinates of point C such that traingle ABC is a right- angled traingle. Sol A is 90 degree set C(3,-2) ==>A(1,0),B(4,3),C(3,-2) B is 90 degree set C(3,4) ==>A(1,0),B(4,3),C(3,4) C is 90 degree set C(1,3) ==>A(1,0),B(4,3),C(1,3)
其他解答:
(因為PQ同XY係parallel..佢地gei slope 係1樣 只要知XY的slope,就知PQ的slope) slope of XY= (0-3) / (-1+3) = -3/2 slope of PQ = (-2-4) / (-4-q) = 6/q+4 slope of XY=slope of PQ -3/2 = 6/q+4 -3q-12 = 12 -3q = 24 q = -8 Let C=(x,y) 1.AB perpendicular to BC 2.BC perpendocular to AC 3.AB perpendocular to AC case1: slope of AB= 3/3 = 1 slope of BC= y-3 / x-4 slope of AB x slope of BC =-1 y-3 / x-4 = -1 y-3 = -x+4 y= -x+7 coordinate of C may be ( x, 7-x) case2: slope of BC= y-3/ x-4 slope of AC= y/ x-1 slope of BC x slope of AC = -1 y^2-3y / x^2-5x+4=-1 y^2-3y = -x^x+5x-4 x^x+y^2-5x-3y+4=0 the coordinate of C may be on the line x^x+y^2-5x-3y+4=0 case3: slope of AB= 3/3 = 1 slope of AC= y/ x-1 slope of AB x slope of AC = -1 y/ x-1= -1 y= 1-x the coordinate of C may be ( x, 1-x) 2009-05-03 20:39:03 補充： 應該係 case2: slope of BC= y-3/ x-4 slope of AC= y/ x-1 slope of BC x slope of AC = -1 y^2-3y / x^2-5x+4=-1 y^2-3y = -x^2+5x-4 x^2+y^2-5x-3y+4=0 the coordinate of C may be on the line x^2+y^2-5x-3y+4=0
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