Pnc Diagonals of a polygon
Hi
I was doing pnc and the question was to find no. of diagonals of a polygon with n sides. I thought that since we take a vertex, and form a line with any other vertex except the 2 vertices adjacent to the first one, it should be (n-2)C2
But my sir said it would be nC2-n, which I agree with and know my method was wrong but dont how it was wrong
Can somebody please point out the flaw in my logic cuz I cant find it
6 Replies
@Apu
Note for OP
+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.(n-2)C2 would mean that the n-2 vertices are fixed which in reality they are not.
It is easy to visualize that the number of choices of 2 sides to be eliminated are n and the number of times a side is overcounted is (n-2). No the actual number would be n*(n-2)C2/(n-2)
Which is the same as nC2-n
kickass effort
we good?
yes
sorry I always forget to close these things 😅
+solved @SirLancelotDuLac
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