幾題數~~~~~ 聽日要交~~~~~~~ (要steps)

我用//當除號,/當分線

1. The maximum absolute error
=0.1/2
=0.05

2. The percentage error
=0.1//2/1.2x100%
=5/1.2
=4.17minutes(correct to 2 decimal places)

3. Let a be the maximum absolute error
a/48.6x100%=5%
100a/48.6=5
100a=243
a=2.43kg
The limits of the actual weight of Ann is
48.6 - 2.43 between 48.6 + 2.43
=46.17 kg between 51.05 kg
4. 4(x+1) : 10 = 2:1
4(x+1) : 10 = 4x+4
4x+4 = 20
4x = 16
x = 4
5. Marbles does A get
=72x3/(3+5)
=216/8
= 27

6. 2x(x-y) - 4y(y-x)
=2x(x-y) + 4y(x-y)
=(x-y)(2x+4y)
=(x-y)(2(x+2y)
=2(x-y)(x+2y)

2. the answer should be 4.17% (correct to 2 decimal places)

1. The maximum absolute error =0.1/2
=0.05cm (一定有單位)
2. The percentage error = 〔(0.1/2)/1.2〕 *100%
= 4.17% (corr. to 2 decimal places)
3. let x be the the maximum absolute error
(x/48.6)100%=5%
x/48.6=0.05
x=2.43
so the maximum absolute error is 2.43kg
so the limitsof the actual weight of Ann is bewteen(48.6-2.43)kg and (48.6+2.43)kg
so the limits of the actual weight of Ann is bewteen(46.17)kg and (51.03)kg
4. 4(x+1):10=1/2 : 1/4
(4x+4)/10=1/2*4/1
(4x+4)/10=4/2
(4x+4)=20
x=4
6. 2x(x-y) - 4y(y-x)
=2x(x-y)-4y〔-(x-y)〕
=2x(x-y)+4y(x-y)
=(x-y)(2x+4y)
5. A gets = 72*〔3/(3+5)〕
=27

1. 0.1 / 2 = 0.05 cm

2. maximum absolute error = 0.1 /2 = 0.05 min
percentage error = (0.05 / 1.2) x 100% = 4.17%

3. maximum absolute error = 48.6 x 5% = 2.43 kg
so, the upper limit = 48.6 + 2.43 = 51.05 kg
lower limit = 48.6 - 2.43 = 46.17 kg

4. 4x + 4 : 10 = 2:1
4x + 4 = 20
4x = 16
x = 4

1. 0.1/2 = 0.05cm
2. of time : 0.1/2 = 0.05
% = 0.05 / 1.2 x 100%
= 4.2%
3. error = 48.6 x 5% = 2.43 kg
limit = 46.17 ~ 51.03 kg
4. 4(x+1) : 10 = 1/2 : 1/4
x+1 = 10/2
x=4
5. A: 72 x 3/(3+5)= 27
6. 2x(x-y) - 4y(y-x)
= 2x(x-y) + 4y(x-y)
= 2(x+2y)(x-y)

2008-01-14 22:52:37 補充：
2. of speed: %= [400 / (1.2-0.05) - 400 / (1.2 0.05)] /400(2) x 100% = 3.5%