PROOF 28
Prove.
1 + 2 + … + n = n(n+1)/2
On the natural numbers ℕ.
Definition D1
S(n) is the sum from 1 to n, defined by S(1) = 1, S(k+1) = S(k) + (k+1).
Proof.
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PROOF 28
1 + 2 + … + n = n(n+1)/2
On the natural numbers ℕ.
Definition D1
S(n) is the sum from 1 to n, defined by S(1) = 1, S(k+1) = S(k) + (k+1).
Proof.
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