证明:1/(1+1)!+2/(2+1)!+…+n/(n+1)!=1-1/(n+1)!

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证明:1/(1+1)!+2/(2+1)!+…+n/(n+1)!=1-1/(n+1)!
证明:1/(1+1)!+2/(2+1)!+…+n/(n+1)!=1-1/(n+1)!

证明:1/(1+1)!+2/(2+1)!+…+n/(n+1)!=1-1/(n+1)!
n/(n+1)!
=(n+1-1)/(n+1)!
=(n+1)/(n+1)!-1/(n+1)!
=
所以原式=1/1!-1/2!+1/2!-1/3!+……+1/n!-1/(n+1)!
=1-1/(n+1)!

用数学归纳法,
k=1时显然成立.
设k=n时,有(1/2!)+(2/3!)+……+n/(n+1)!=1-1/(n+1)!
当k=n+1时,
(1/2!)+(2/3!)+……+n/(n+1)!+(n+1)/(n+2)((n+1)!
=1-1/(n+1)!+(n+1)/(n+2)((n+1)!
=1-1/(n+2)!
命题得证