作者r19891011 (弧形)
看板trans_math
标题Re: [积分] 求面积和一题极限
时间Sat Feb 6 00:56:46 2010
※ 引述《BIEGABOY (BIEGABOY)》之铭言：
: 1.Find the area of the region bounded by the curve x=tcost,y=tsint,
: 0<=t<=pi ,and the x-axis.
画成极座标︰r=θ
π 1 2 3
所求=∫ ---r dθ=π /6
0 2
: 2.lim [ (x^98+2009x^97+1)^1/98-x ]
: x->无限大 -1 -98
-1 -98 1/98 1/98 x(2009x +x )
原式=lim x[(1+2009x +x ) - 1 ]=lim ---------------------------------
x→∞ x→∞ (1+2009x^-1 +x^-98)^97/98 +...+1
n n n-1 n-2 n-1
=2009/98 ，其中a -b =(a-b)(a +a b+...+b )
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