find the constant term in the expansion of (2x^2+1/x)^9
我知個答案係
=9Cr(2x^2)^9-r(1/x)^r
=9Cr ．2^9-r．x^18-3r
18-3r=0
r=6
個term係672
但我唔知條式第二行2^9-r ．x^18-3r 點離
help me~~~
add math 困難問題,請高手指點~~
2007-12-27 11:11 pm
回答 (1)
2007-12-27 11:18 pm
✔ 最佳答案
Solution:圖片參考：http://hk.geocities.com/stevieg_1023/rr1.gif
2007-12-27 15:19:02 補充：
(ab)^n=(a^n)(b^n)
收錄日期: 2021-04-25 17:17:37
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071227000051KK02349