已知数列an中,a1=2,an+1=an+2(n属于N*)数列bn满足bn=1/anan+1,求bn前十项和

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已知数列an中,a1=2,an+1=an+2(n属于N*)数列bn满足bn=1/anan+1,求bn前十项和
已知数列an中,a1=2,an+1=an+2(n属于N*)数列bn满足bn=1/anan+1,求bn前十项和

已知数列an中,a1=2,an+1=an+2(n属于N*)数列bn满足bn=1/anan+1,求bn前十项和
a(n+1)=an+2
a(n+1)-an =2
an -a1 =2(n-1)
an = 2n
bn=1/[an.a(n+1)]
= (1/4)( 1/n - 1/(n+1)]
Sn =b1+b2+...+bn
= (1/4)( 1 - 1/(n+1)]
= n/[4(n+1)]
S10 = 10/44 = 5/22