推 math1209:你的分母是 0 if x = k(pi). 展開後, 依 114.32.219.116 04/12 20:20
→ math1209:然是 0. 114.32.219.116 04/12 20:20
→ mmmaaatttttt:這不能用次方比大小吧，上下都是無窮 111.250.192.93 04/12 20:21
→ math1209:換言之, 跟展不展開沒什麼關係 = = 114.32.219.116 04/12 20:22
→ midarmyman:分母是零? 不懂 140.117.198.78 04/12 20:32
→ midarmyman:分子分母同除分子的最高次 140.117.198.78 04/12 20:32
推 math1209:分母部分為 x^2 sin^2 x = g(x). 114.32.219.116 04/12 20:32
→ midarmyman:分母的次方不是一定比較大? 140.117.198.78 04/12 20:33
→ math1209:只要 x = k(pi), g(x) 都是 0. 114.32.219.116 04/12 20:33
→ math1209:即使你將 sin^2 x 展開寫為 h(x) = ... 114.32.219.116 04/12 20:33
→ math1209:你的分母還是 x^2 h(x) = g(x). 114.32.219.116 04/12 20:33
→ math1209:注意, 等號在數學上可是很強的條件... 114.32.219.116 04/12 20:33
→ math1209:簡單的說, 定義 h(x) = sin^2 x. 114.32.219.116 04/12 20:34
→ math1209:即使你將 h(x) 寫成 Taylor 展開 114.32.219.116 04/12 20:35
→ math1209:他依然得滿足 h( k (pi) ) = 0 . 114.32.219.116 04/12 20:35
→ midarmyman:懂你意思! 還是要照原函數來看比較準QQ 140.117.198.78 04/12 20:35
→ midarmyman:那我let x=1/t再展開 不就行了? 140.117.198.78 04/12 20:38
→ midarmyman:就是零 顆顆 140.117.198.78 04/12 20:38
※ 編輯: midarmyman 來自: 140.117.198.78 (04/12 22:51)
推 keith291:non well-defined 61.216.60.19 04/12 23:24
→ keith291:取n=kπ,n→∞ as k→∞ 此時即限不存 61.216.60.19 04/12 23:26
※ 編輯: midarmyman 來自: 140.117.198.78 (04/12 23:46)