已知数列{an}满足a1=33,an+1-an=2n 则求an/n的最小值

来源：学生作业帮助网编辑：作业帮时间：2024/05/01 17:14:47

已知数列{an}满足a1=33,an+1-an=2n 则求an/n的最小值
已知数列{an}满足a1=33,an+1-an=2n 则求an/n的最小值

已知数列{an}满足a1=33,an+1-an=2n 则求an/n的最小值
a(n+1)-an=2n
an-a(n-1)=2(n-1)-----------(1)
a(n-1)-a(n-2)=2(n-2)-------(2)
……………………
a2-a1=2×1-------------- (n-1)
(1)+(2)+...+(n-1)得 an-a1=2×[1+...+(n-2)+(n-1)]=2×[1+(n-1)](n-1)/2=n(n-1)
∴an=a1+n(n-1)=n²-n+33
an/n=n-1-33/n=n+33/n-1≥2√33-1
所以：n=33/n
所以：n=√33
n=5或者n=6
a5/5=5+33/5-1=10.6,a6/6=6+33/6-1=10.5

已知数列{an}满足a1=1 an+1=an/(3an+1) 则球an 已知数列{an}满足an+1=an+n,a1等于1,则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=33,an+1-an=2n 则求an/n的最小值已知数列{an}满足a1=33,an+1-an=2n 则求an/n? 已知数列an满足a1=33 an+1 -an=2n 则an/n的最小值是? 已知数列{an}满足a1=33,an+1-an=2n,则an/n的最小值为已知数列{an}中满足(An+1-An)(An+1+An)=16,且a1=1,an 已知数列{an}满足a(n+1)=an+n,a1=1,则an= 已知数列an满足an=1+2+...+n,且1/a1+1/a2+...+1/an 已知数列满足a1=1 ,an+1+2an=2 求an 已知数列{an}满足a1=1,an+1·an=2^n 则s2012 已知数列{an}满足An+1=2^nAn,且A1=1,则通项an 已知数列an满足条件a1=-2 an+1=2an+1则a5 已知数列{an}满足a(n+1)=an+lg2,a1=1,求an 已知数列｛an｝满足an=an+1 -lg2,且a1=1,则通项公式为? 已知数列{an},满足a1=1/2,Sn=n²×an,求an 已知数列{an}满足a1=1/2,sn=n^2an,求通项an