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| bio | website | |
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| age | ||
| visits | member for | 2 years, 9 months |
| seen | Jul 1 '12 at 12:34 | |
| stats | profile views | 26 |
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Dec 28 |
awarded | Nice Question |
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Sep 7 |
awarded | Notable Question |
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Nov 15 |
awarded | Popular Question |
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Aug 13 |
comment |
Proof for formula for sum of sequence $1+2+3+\ldots+n$? Here's the only pic I could find that shows the visual proof you describe: aplcenmp.apl.jhu.edu/Classes/605202/felikson/lectures/L2/… |
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Aug 13 |
awarded | Supporter |
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Aug 12 |
comment |
Proof for formula for sum of sequence $1+2+3+\ldots+n$? Holy crap! I don't speak mathematics but thx anyway. |
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Aug 12 |
comment |
Proof for formula for sum of sequence $1+2+3+\ldots+n$? Yep, that's it, write one backwards. I read this post but it didn't click - I guess I needed to write it out to see it. Thx |
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Aug 12 |
revised |
Proof for formula for sum of sequence $1+2+3+\ldots+n$? added tag algebra |
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Aug 12 |
awarded | Scholar |
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Aug 12 |
awarded | Editor |
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Aug 12 |
accepted | Proof for formula for sum of sequence $1+2+3+\ldots+n$? |
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Aug 12 |
revised |
Proof for formula for sum of sequence $1+2+3+\ldots+n$? added 93 characters in body |
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Aug 12 |
comment |
Proof for formula for sum of sequence $1+2+3+\ldots+n$? I got it! It's 2S = (1+2+...+(n-1)+n) + (n+(n-1)+...+2+1) - so you write one backwards, then match up each term. 2S = (1+n) + (2+n-1)+...+(n-1+2)+n+1, and so 2S=(n+1)+(n+1)+...+(n+1)+(n+1) etc |
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Aug 12 |
comment |
Proof for formula for sum of sequence $1+2+3+\ldots+n$? Well, you lost me at "each term is n+1...". As far as I can see, if you add the two equations term by term it will be: n+n + (n-1)+(n-1) + ... + 2+2 + 1+1. How did you get (n+1) + (n+1) + ... + (n+1)? |
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Aug 12 |
awarded | Student |
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Aug 12 |
asked | Proof for formula for sum of sequence $1+2+3+\ldots+n$? |
