推 thebronjames: 感謝 04/01 01:58
※ 引述《thebronjames (LBJ)》之銘言：
: https://i.imgur.com/UABgVqf.jpg
: 這題怎解？
: 拜託各位了
1/sin(x)^2 - 1/x^2
= [x^2 - sin(x)^2]/(xsin(x))^2
= (x)(1 + sin(x)/x)(x - sin(x))/(x^2 sin(x)/x)^2
取極限後
-> 2 / 3! = 1/3
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