ADD MATH 题目-form 4 Chp 6&7

CCHAPPY

第1题是chapter 7的,后2题是chapter 6.本人尤其对coordinate geometry生疏，请他大家帮帮忙

longcy

1. (i) let P(x, y)
AP=AB
(x-3)^2 + (y-2)^2 = (0-3)^2 + (-2-2)^2
x^2+y^2-6x-4y+13=25
x^2+y^2-6x-4y-12=0

（ii) sub (0,p) into x2+y2-6x-4y-12=0
p2-4p-12=0
(p-6)(p+2)=0
p=6 or p=-2
kindly info the answer provided by the book, pls tell me which book.

1. (a) MPN = MPQ
(t+9)/(-2-6)=(6+9)/(-4-6)
t=3

(b)

using the cross multiply concept
x-coor for M = [-4(1)+6(4)]/(1+4)
= 4
y-coor for M = [6(1)+(-9)(4)]/(1+4)
= -6
thus, M(4, -6)

2.
MPR = 1/3
MPQ=-3
thus, eq PQ is y=-3x+6
Solve eq PQ and eq PR
-3x+6=1/3x-2
x=2.4
sub x=2.4 into eq PR or eq PQ
y=-1.2
thus, P(2.4, -1.2)

CCHAPPY

longcy 发表于 25-6-2013 09:56 AM
1. (i) let P(x, y)
AP=AB
(x-3)^2 + (y-2)^2 = (0-3)^2 + (-2-2)^2

谢谢！
PELANGI

CCHAPPY

longcy 发表于 25-6-2013 09:56 AM
1. (i) let P(x, y)
AP=AB
(x-3)^2 + (y-2)^2 = (0-3)^2 + (-2-2)^2

can u aslo help me solve this question?pls~

Find
(a) the coordinates of point F,
(b) the gradient of the straight line FD,
(c) the y-intercept of the straight line FD.

Ans: (a)F(-5, 3)
        (b)-3
        (c)-12

longcy

(a) Since DE =5,
thus EF = 5 and F(-5, 3)
(b) D(-4, 0)
M FD=(3-0)/(-5+4)
=-3
(c) Eq of FD is
y-0=-3(x+4)
y=-3x-12
thus y-intercept = -12