2條數學題(指數)

2008-05-24 8:42 am
我想知過程 ,不明白負數的如何計算
Simplify
1.
(-2r^4 S^-3)^-2

答案是:s^6/4r^8

2.
(2m)^-3 s^-5
---------------
4n^-1s^-2

答案是:n/32m^3s3

THANKS^^

回答 (2)

2008-05-24 7:41 pm
✔ 最佳答案
1.(-2r^4 S^-3)^-2

=-2(-2)r^4(-2)s^-3(-2)

=4r^-8s^6

=s^6/4r^8 (因為4r^-8=1/4r^8)

2.(2m)^-3 s^-5/4n^-1s^-2

=s^-5 n/(2m)^3 4s^-2

=n/8m^3 4s^(5-2)

=n/32m^3s^3

咁樣係咪快好多呢?哈哈>.<

其實呢條係f.2定f.3?

唔明可以再問我
參考: 自己做得多鑽研出黎的
2008-05-24 9:21 am
我既做法係將負指數變哂做正指數再計
*負指數即係1 OVER 幾多
例如2^-2=1/2^2=1/4
1.
     4 -3  -2
(-2R S  )

     1
= _______________
     4 -3  2
(-2R S  )

     1        2
= ______________ (註:-2   = -2 x-2=4)
    8 -6 
  4R S

     6
    S
= _______________
      8
   4R



2.
    -3 -5
 (2M) S
= _____________
    -1 -2
  4N S

     1  2
   N S   
= ______________ (註:4無負指數是不用調的,陷阱)
     3  5
 4(2M) S


    N   
= ______________
     3 3
  32M S


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