作者RAINDD (标签贴爽了没？)
看板trans_math
标题Re: [积分] 一题积分
时间Fri Dec 8 23:06:01 2006
※ 引述《pobm (待从头收拾旧河山)》之铭言：
: dx
: ∫ --------------
: 1+(cosx)^2
(sec(x))^2 1
= ∫ ----------------- dx = ∫ ----------------- d(tan(x))
1 + (sec(x))^2 2 + (tan(x))^2
1 1/√2
= ∫ ----------- dt {令 t = tan(x) } = (1/√2)∫ ---------------- dt
2 + t^2 1 + (t/√2)^2
= (1/√2) arctan(t/√2) + constant
= arctan(tan(x)/√2) / √2 + constant
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 61.64.93.146
1F：推 pobm:谢谢^^ 61.229.155.20 12/08 23:57