數學題 識 La place trans form 的請進

2010-03-16 10:55 am
小弟D功課

唔知係唔係咁做

請有識之士指點一下

thx

題目係咁樣的
請找出電流 (當電掣閉合後) 如圖 R = 160 ohm, L = 1 H, C = 100uF and E = 20 V

圖片參考:http://i283.photobucket.com/albums/kk288/byfrgnhvt/301.jpg


圖片參考:http://i283.photobucket.com/albums/kk288/byfrgnhvt/2323.gif

亞sir 要我地用La place trans form 做唔之咁樣啱唔啱

請幫下小弟啦

THX THX THX

回答 (2)

2010-03-16 5:47 pm
✔ 最佳答案
Starting from line 7:

I[R + sL + 1/(Cs)] = E/s

I(CRs + CLs2 + 1)/(Cs) = E/s

I(CLs2 + CRs + 1) = CE

Sub all those given values, we have:

I(0.0001s2 + 0.016s + 1) = 0.002

I(s2 + 160s + 10000) = 20

I[(s + 80)2 + 3600] = 20

I[(s + 80)2 + 602] = 20

I = 20/[(s + 80)2 + 602]

= (1/3) {60/[(s + 80)2 + 602]}

Taking inverse Laplace transform:

i(t) = (1/3) e-80t sin 60t
參考: Myself
2010-03-16 4:33 pm
Line 7 should be I(R + sL + 1/Cs) = E/s if L(di/dt) really = sI.


收錄日期: 2021-04-25 22:38:19
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100316000051KK00206

檢視 Wayback Machine 備份