In the expansion of (x^2+2)^n in descending powers of x,where n is a positive integer,the coefficient of the third term is 40.Find the value of n and the coefficient of x^4.
我識一半ng識一半= =
x^2n+(nC1(x^2)^x-1(2)+.....
the third terms = nC2 (2)^2x^2n-4
4(nC2)=40
n=5
之後唔識搵la
同埋唔明 ,有勞丫
binomial expansion
2008-10-18 6:25 pm
回答 (1)
2008-10-18 6:54 pm
✔ 最佳答案
Explanation as follows:圖片參考：http://i238.photobucket.com/albums/ff245/chocolate328154/Maths517.jpg?t=1224298428
參考: My Maths Knowledge
收錄日期: 2021-04-15 19:12:14
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