- #1

Ben2

- 37

- 9

*Disquisitiones Arithmeticae*, p. 10: Let "*" indicate multiplication and "^" indicate "to the power." For real numbers a, b, c,..., let [a] = a, [a,b] = b*a+1, [a,b,c] = c*[a,b]+[a], [a,b,c,d] = d*[a,b,c]+[a,b], etc. Prove that [a,b,...,l,m]*[b,c,...,l] - [a,b,...,l]*[b,c,...,m] = (-1)^n, where n is the number of elements in the set {a,b,...,l,m}.

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