已知数列{an},a1=2,an+1=an+2n,则数列的通项公式an=?

来源：学生作业帮助网编辑：作业帮时间：2024/04/27 22:30:39

已知数列{an},a1=2,an+1=an+2n,则数列的通项公式an=?
已知数列{an},a1=2,an+1=an+2n,则数列的通项公式an=?

已知数列{an},a1=2,an+1=an+2n,则数列的通项公式an=?
an+1=an+2n
推出
an=an-1+2(n-1)
.
.
.
a2=a1 + 2
累加得
an = a1 + 2(2+3+4+...n-1)
an = 2 + n(n-1)
an = n^2 - n+2 (n>=1)

已知数列{an},A1=1 A(n+1)=2an/an+2 求a5 已知数列｛an｝中,a(n+1)=an+2^n,a1=3,求an 已知数列an满足条件a1=-2 a（n+1）=2an/(1-an) 则an= 已知数列an满足a1=1,a(n+1)=an/(3an+2),则an=? 已知数列｛an｝中a1=1/2,a(n+1)=(2an)/(4an+3),求an. 已知数列{an},a1=1,a(n+1)=an^2+an+1,求通项公式an 已知数列{An}中,A1=1,A(n+1)=An/(1+2An),求An 已知数列{an}中,a1=1/2,an+1+3an=0,an=( ) 已知数列｛an｝,a1=1,an+1=2an/an+2,求a5 已知数列an,a1=1 an+1-an=2的n次幂求an 已知数列{an}满足an+1=2an+3.5^n,a1=6.求an 已知数列｛An｝满足a1=1,a（n+1）=2an+1 求证数列{an+1}是等比数列求数列｛an｝通式数列题,求通项已知数列｛An}满足A=2An/(1-An),A1=2,求数列｛An}的通项公式已知数列满足a1=1/2,an+1=2an/(an+1),求a1,a2已知数列满足a1=1/2,a(n+1)=2an/(an+1),求a1,a2;证明0 已知数列{an}满足a(n+1)=an+n,a1=1,则an= 已知数列{an}满足a(n+1)=an+lg2,a1=1,求an 几个数列问题.已知数列{an} a1=1,an+1=an/(1+n^2*an) 求an 已知数列{an} 满足a1=1 a1*a2*a3.*an=n^2 求an 已知数列{an}满足a1=2,a(n+1)-an=a(n+1）*an,则a31=?