推 StellaNe :奇異點? 07/03 20:02
→ derek0906 :singular point 07/03 20:21
→ yueayase :1/1+y = Σ(-y)^n, y = 2x^2, x乘進Σ裡 07/04 00:51
→ yueayase :沒有奇異點,應該就要有power series, 收斂半徑應該 07/04 00:53
→ yueayase :可用ratio test, root test, 和geometric series一樣 07/04 00:54
→ derek0906 :看不太懂.. 07/04 03:36
推 suhorng :所以你會泰勒展開式嗎...? 07/04 09:18
→ catsnow :用等比級數公式就夠了吧... 07/04 11:05
→ derek0906 :等比級數算出來是這樣x/2[1+1/(1/2+x^2)+...]對嗎? 07/04 19:53
→ derek0906 : -號才對 07/04 19:54
→ derek0906 :(1/2-x^2) 07/04 19:54