1/2（1-1/2n+1）化简,急啊!
问题描述：
1/2（1-1/2n+1）化简,急啊!
答
1/2[1-1/(2n+1)]
=1/2[(2n+1)/(2n+1)-1/(2n+1)]
=1/2[(2n+1-1)/(2n+1)]
=1/2*2n/(2n+1)
=n/(2n+1)