兩條數要問
呢條b part 個答案係咩.......
2.John calculates the mean height of his classmates to be 162.3cm correct to 0.1cm
Find the maximum percentage error.
答案係唔係0.0308%???
[ 本帖最後由 frankie172002 於 1-5-2008 11:19 編輯 ] 你唔俾part A 個 result,我又點計個B 呢. 即係問晒成條啦.
A) 10^2 - x(x+1)/2 - (10-x)10/2 - (9-x)10/2
= 100 - 1/2 ( x^2 + x + 100 - 10x + 90 - 10x)
= 100 - 1/2(x^2 - 19x + 190)
= -0.5x^2 + 9.5x + 5
-0.5x^2 + 9.5x + 5 <= 35
x^2 - 19x + 60 >= 0
x <= 4 or x >= 15
error = 0.05
percentrage error = 0.05/162.3 = 0.0308% sor...唔記得放第一條a part個答案
但係第一條我計完同你個答案一樣.......但係個答案.......
個x>=15應該係要reject
但係最後果兩行唔明點解........
回復 3# 的帖子
條邊長得10cmso x+1要<=10
x<=9 原帖由 L.K. 於 1-5-2008 12:11 發表 http://www1.nakuz.com/bbs/images/common/back.gif
條邊長得10cm
so x+1要
但係點解x<=9???
如果佢x=9,條AN咪=10cm lo,但係佢對上仲有條ND架wo......
回復 5# 的帖子
咁nd就=0..... 原帖由 L.K. 於 1-5-2008 12:21 發表 http://www1.nakuz.com/bbs/images/common/back.gif咁nd就=0.....
咁就唔係一個square la......... 原帖由 frankie172002 於 1/5/2008 12:46 發表 http://www.nakuz.com/bbs/images/common/back.gif
咁就唔係一個square la.........
WHY?
for x=9
l
l
l
v 原帖由 L.K. 於 1-5-2008 12:53 發表 http://www1.nakuz.com/bbs/images/common/back.gif
WHY?
for x=9
l
l
l
v
係wo.........
咁點解個答案係4<x<=9
就咁0<x<=9唔得咩? 兩個constraint 應該 and 埋一齊, 而唔係 or 埋一齊,所以答案應該係 0 <= x < 4
if 4 < x <= 9 , then area > 35cm^2
我用excel做左一次
x area
0 5
1 14
2 22
3 29
4 35
5 40
6 44
7 47
8 49
9 50
10 50
11 49
12 47
13 44
14 40
15 35
16 29
17 22
18 14
[ 本帖最後由 【YU】 於 1-5-2008 13:30 編輯 ]
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