作者SDUM (Roger)
看板trans_math
标题Re: [考古] 中兴近五年考古
时间Fri Dec 19 23:17:06 2008
※ 引述《popop922902 ()》之铭言：
: 1.FIND the taylor's series at x=0 of the function f(x)=更号(1+X)
: 2.lim [更号(4x^2+5x+2) +2x]
: x->负无穷大
--------------------------------------------------
∞
1.f(x) = Σ (0.5Ck)(x^k)
k=0
2. lim {√(4x^2+5x+2)+2x}
x->-∞
5 2
= lim {|x|√(4+ ── + ── ) +2x}
x->-∞ x x^2
5 2
= lim {-x√(4+ ── + ── ) +2x}
x->-∞ x x^2
2-√(4+ 5/x + 2/(x^2))
= lim ─────────────
x->-∞ 1/x
= -5/4
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 218.175.77.240
1F：推 popop922902:第二提的第二步看不懂..210.240.176.170 12/19 23:34
2F：推 triumph323:同除X阿 但是他是平方所以加绝对值203.121.241.103 12/20 01:52
3F：→ triumph323:在判别X趋近正还负在判断203.121.241.103 12/20 01:53
4F：→ triumph323:不是同除 说错 应该是把X提出去203.121.241.103 12/20 01:53
5F：→ kingalan:令x=-t 带入比较好了解 163.23.231.88 12/20 07:19