第五條...
請指教..
更新1:
myisland8132 , 介唔介意講多小小.. i want to learn more .. how about the last part of b , ds=dsn of
更新2:
do we need to use cross product of JxN
請數學高手指教, 小弟真係唔識做..
回答 (1)
2008-01-28 6:46 am
✔ 最佳答案
n=r outward normalF.n=kr^n
ds=r^2sinθdθdφ
∫∫f.n ds
=∫∫ka^n A^2sinθdθdφ
=4πk(A^n+2)
the second part is 0 since F*n=0
2008-01-28 15:39:48 補充：
do we need to use cross product of JxN 應該不需要﹐因為F*n與n垂直
2008-01-28 15:40:36 補充：
F*n=0 打錯了
收錄日期: 2021-04-25 16:57:52
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080127000051KK03338