中二數學問題..快進來解答解答!THX

2011-10-05 6:51 am

1. the reading of a thermometer is 37.5度 with a percentage error of 2/2/3%.
(a) find the max. absolute error.
(b) (i) find the upper and lower limits of the actual reading.
(ii) Hence,is it possible that the actual reading is 38.8度?Explain your answer.

30. A picture frame is in the shape of a rectangle.All the measurements are shown in the figure and are correct to the nearest cm.Find the max. and min. areas of the picture frame.

更新1:

picture frame: 86cm x 58 cm picture: 70cm x 42 cm

回答 (2)

[匿名]

2011-10-05 1:13 pm

✔ 最佳答案

we cannot do no.30 because you have no figure
no.1 I am thinking....

2011-10-05 05:13:26 補充：
1(a)Let the max absolute error be x
x/37.5X100%=2/2/3%
x=1
the max absolute error is 1

1(b)(i)The upper limits=38.5
The lower limits=36.5
1(b)(ii)no

(something like that......I am not sure....If it is wrong sorry)

2011-10-06 00:35:20 補充：
30.Thanks...
The max absolute error
=1X1/2
=0.5
The upper limit numbers
=86.5cmX58.5cm
=70.5cmX42.5cm
The max area of picture frame
=86.5X58.5-70.5X42.5cm^2
=2064cm^2
The lower limit
=85.5cmX57.5cm
=69.5cmX41.5cm
The min area of picture frame
=85.5X57.5-70.5X41.5cm^2
=1990.5cm^2

p.s我係英國

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嘉茵

2011-10-05 7:53 pm

(a) Let x be the maximum error
x/37.5 x 100% = 2/2/3%
x/37.5 = 8/300
x = 8/300 x 37.5
x = 1
So, absolute error = 1
(bi) the upper limit
=37.5℃+1
=38.5℃
the lower limit
=37.5℃-1
=36.5℃
(bii) the range of the possible actual value (say x cm) is
36.5℃ ≦ x℃＜38.5℃
∴the actual reading can not be 38.8℃

30) 什麼資料也沒有！！

P.S. 一定對！：

參考: me

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