推 shinyhaung:第二行微分就錯了 最好拆成ln相減再微 02/05 13:55
推 CRAZYAWIND:錯~~~很~~~大~~~ 02/05 13:59
→ CRAZYAWIND:先拆成-1/t L^-1 d/ds [ln s^2+1 -ln s^2-2s+1] 02/05 14:00
→ t5d:ln微分不單單變倒數而已 內部的項還要再對x微分一次 02/05 14:11
→ mdpming:痾... 02/05 15:34
2
-1 s + 1
L [ln----------]
2
(s - 1)
答案
2 t
---(e - cost)
t
幫我檢查哪裡錯...
2
1 -1 d s + 1
- --- L [ --- ln ------- ]
t ds 2
(s-1)
2
1 -1 s - 2s +1
= - --- L [ ----------- ]
t 2
s + 1
2
1 -1 s -1 s -1 1
= - --- { L [ ------- ] - 2 L [ ------- ] + L [ -------- ]
t 2 2 2
s + 1 s + 1 s + 1
1 d -1 s
= - ---[ --- L [ ------- ] - 2cost + sint ]
t dt 2
s + 1
1
= - ---[-2cost] ..............................
t
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