考慮直角坐標平面上的三點P(-2,1) Q(3,5)及 R(1,r)
a, 求PQ的斜率 (須列式計算)
b, 若QR的斜率為-1,求r的值 (須列式計算)
數學一問!!! 15分
2006-12-27 8:23 am
回答 (2)
2006-12-27 8:26 am
✔ 最佳答案
(a)PQ的斜率
=(5-1)/(3+2)
=4/5
(b)
QR的斜率為-1
(r-1)/(1-3)=-1
r-1=2
r=3
2006-12-27 00:27:32 補充：
(b)應是(r-5)/(1-3)=-1r-5=2r=7
2006-12-27 00:40:43 補充：
由題意(x+5)/2=3,x=1(y+3)/2=5,y=7
2006-12-27 9:24 am
a)
m=(5-1) / [3- (-2)] = (5-1) / (3+2) =4/5
b)
(r-5) / (1-3) = -1
r-5 = 2
r = 7
c) by mid-pt theorem,
(x+5) /2 =3
x+5 = 6
x=1
(3+y) / 2 =5
3+y=10
y=7
m=(5-1) / [3- (-2)] = (5-1) / (3+2) =4/5
b)
(r-5) / (1-3) = -1
r-5 = 2
r = 7
c) by mid-pt theorem,
(x+5) /2 =3
x+5 = 6
x=1
(3+y) / 2 =5
3+y=10
y=7
參考: Answer book
收錄日期: 2021-04-12 22:35:56
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