循環小數化分數點計???
以下循環小數化分數點計???(括號裏的是循環小數)
1. 0.(6)
2. 0.7(4)
3. 0.(45)
4. 0.9(4)
5. 0.(148)
6. 0.5(678)
回答 (2)
✔ 最佳答案
(1) Let x = 0.(6)
10 x = 6.(6)
Then 10 x - x = 6
9x = 6
x = 2 / 3
(2) Let x = 0.7(44)
10x = 7.(44)
100x = 74.(44)
Then 100x - 10x = 67
90x = 67
x = 67 / 90
( 3 ) Let x = 0.(45 )
100x = 45.(45)
Then 100x - x = 45
99x = 45
x = 5 / 11
( 4 ) Let x = 0.9(4)
10 x = 9.(4)
100x = 94. (4)
Then 100x - 10x = 85
90x = 85
x = 17 / 18
( 5 ) Let x = 0.(148)
1000x = 148.( 148)
Then 1000x - x = 148
999x = 148
x = 4 / 27
( 6 ) Let x = 0.5(678)
10x = 5.(678)
10000x = 5678.(678)
Then 10000x - 10x = 5673
9990x = 5673
x = 1891/3330
參考: My Maths Knowledge
1. 0.66666666666666666.............=x
10x=6.66666666666666666666666666666666................
9x=6.000000000000000............................
x=2/3
2. 0.7444444444444444444444444..............=x
100x=74.44444444444.........................
90x=67.00000000000000000000000
x=67/90
3. 0.4545454545454545.................=x
100x=45.45454545.................
99x=45.00000000................
x= 45/99
4. 0.9444444444444444............=x
100x=94.4444444444444444444444.............
90x=85.0000000000000000000000..........
x= 85/90
= 17/18
5. 0.148148148..................=x
1000x=148.148148148.....................
999x=148.0000000000000000000000000.........
x=148/999
=4/27
6. 0.5678678678678678...........=x
10000x=5678.678678678............
9990x=5673.0000000000000000....................
x=5673/9990
=1891/3330
收錄日期: 2021-04-29 19:42:53
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