倫倫的小blog

星期二要交的EM作業中有一題：

我早上算了老半天，就快證明成功了，但是就是差那麼一些係數湊不起來，

想破頭了，不知道是不是typo，

就寫信去給教授！！

Dear Professor Jorge, (他是很好很好的教授！！)

I want to confirm that in problem 8,



I am not sure whether I have mistakes in my calculation or there is a typo.




that will match the potential produced by the image charge.

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今天下午收到回信：

I don't think that there is any typo.

However, your figure seems to show the image charge located at "d"
when it is actually located at d'=a*a/d. Hope this helps.

幹！瞬間我懂了，原來是我把 d' 寫成d了

這就是頓悟阿

就這樣花了快四小時一直思考與檢查。。。。。。