[積分] 極限

看板trans_math作者 (mo)時間12年前 (2012/02/14 18:02), 編輯推噓1(109)
留言10則, 3人參與, 最新討論串14/14 (看更多)
1.lim sinx-sin(sinx) ──────── x→0 x^3 答案:六分之一 2.lim x→ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 220.134.48.197

02/14 20:40, , 1F
sin(sin(x))=sin(x)-(sin(x))^3/3!+O(x^5)
02/14 20:40, 1F

02/15 11:06, , 2F
1.就用羅必達上下約分答案就出來了~
02/15 11:06, 2F

02/15 17:10, , 3F
L'Hospital雖然較快, 但一樓的寫法會嚴謹些
02/15 17:10, 3F

02/15 17:11, , 4F
填充題就用L'hospital吧...計算題就...
02/15 17:11, 4F

02/15 20:44, , 5F
L-rule 會比較快嗎? 我前面的展式把分子變成
02/15 20:44, 5F

02/15 20:44, , 6F
(sin(x))^3/3!+O(x^5), 所以立即得答案 1/3!
02/15 20:44, 6F

02/15 20:45, , 7F
而L-rule分子是 cos(x)-cos(sin(x))cos(x)
02/15 20:45, 7F

02/15 20:46, , 8F
cos(x) 提出, 變成 [1-cos(sin(x))]/(3x^2)
02/15 20:46, 8F

02/15 20:46, , 9F
= {[1-cos(sin(x))]/[3(sin(x))^2]}*
02/15 20:46, 9F

02/15 20:47, , 10F
(sin(x))^2/x^2
02/15 20:47, 10F
文章代碼(AID): #1FEZ4kea (trans_math)
討論串 (同標題文章)
文章代碼(AID): #1FEZ4kea (trans_math)