Re: [積分] 一題積分
※ 引述《pobm (待從頭收拾舊河山)》之銘言：
: 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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12/08 23:57, , 1F
12/08 23:57, 1F
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