若 1/X1 + 1/X2 + 1/Xn = 1,且X1, X2, Xn均不相等,X1=? X2=? Xn=?
答案是: 2,3,6
若 1/X1 + 1/X2 + 1/X3 + 1/Xn = 1,且X1, X2, X3, Xn均不相等,X1=? X2=? X3=? Xn=?
答案是: 2,3,7,42
看出規則了沒?
若 1/X1 + 1/X2 + 1/X3 + ... + 1/Xn = 1,Xn=?
X1 = 2
X2 = X1 + 1 = 3
X3 = X1 X2 + 1 = 7
X4 = X1 X2 X3 + 1 = 43
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X(n-1) = X1 X2 X3 ... (Xn-2) + 1
Xn的答案是:X1X2X3...X(n-1)