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I don't know the name of this but it seems that I have some kind of a problem solving illness. It has happened many times in my life that my close friends make fun of it from time to time. The problem is, sometimes when I think about something, its not the simplest solution that comes to my mind and its the more complicated solutions that comes to my mind first!
For example today someone asked me how to prove that the degeneracy of hydrogen atom energy levels(not considering fine structure) is ##n^2##. The solution is to compute the sum ## \displaystyle \sum_{l=0}^{n-1} (2l+1) ##. And this is what I sent him:
## \displaystyle \sum_{l=0}^{n-1} (2l+1)=\sum_{l=0}^{2n-1} l-\sum_{l=0}^{n-1} 2l=n(2n-1)-n(n-1)=2n^2-n-n^2+n=n^2 ##
But, there is an easier way to do the sum:
## \displaystyle \sum_{l=0}^{n-1} (2l+1)=2\sum_{l=0}^{n-1} l+\sum_{l=0}^{n-1} 1=n(n-1)+n=n^2##.
What is this illness? How can I cure it?
For example today someone asked me how to prove that the degeneracy of hydrogen atom energy levels(not considering fine structure) is ##n^2##. The solution is to compute the sum ## \displaystyle \sum_{l=0}^{n-1} (2l+1) ##. And this is what I sent him:
## \displaystyle \sum_{l=0}^{n-1} (2l+1)=\sum_{l=0}^{2n-1} l-\sum_{l=0}^{n-1} 2l=n(2n-1)-n(n-1)=2n^2-n-n^2+n=n^2 ##
But, there is an easier way to do the sum:
## \displaystyle \sum_{l=0}^{n-1} (2l+1)=2\sum_{l=0}^{n-1} l+\sum_{l=0}^{n-1} 1=n(n-1)+n=n^2##.
What is this illness? How can I cure it?