等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?
来源：学生作业帮助网 编辑：六六作业网 时间：2024/12/20 12:04:03
等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?等差数列列｛an｝的前n项和为Sn,
等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?
等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?
等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?
a(n)=a+(n-1)d,[a(n)]^2=[a+(n-1)d]^2=[nd+a-d]^2,
s(n)=na+n(n-1)d/2=(d/2)n^2+n(a-d/2),
s(n)/[a(n)]^2=[(d/2)n^2+n(a-d/2)]/[nd+a-d]^2=[d/2+(a-d/2)/n]/[d+(a-d)/n]^2,
lim(n->无穷大){s(n)/[a(n)]^2}=lim(n->无穷大）{[d/2+(a-d/2)/n]/[d+(a-d)/n]^2}=(d/2)/d^2=1/(2d)
d=2
lim(n->无穷大){s(n)/[a(n)]^2}=0.25
Sn是n的一次式，an^2是n的二次式，极限是0
lim(n→∞)[n*a1^2+n*(n-1)*d]/2*[a1+(n-1)d]^2=1/d=1/2
4分之1
张家琛wd 正确
记数列{an}的前n项和为Sn,若{Sn/an}是公差为d的等差数列,则{an}为等差数列的充要条件是d=?
等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?
等差数列an中,公差d>0,且a5+a10=0,记数列-2/an的前n项和为Sn,则使Sn
等差数列{an}的前n项和为Sn,公差d
记数列an前n项和为Sn,数列Sn/an是公差为d的等差数列,则数列an为等差数列时,d=1/2 和1
已知{an}是首项为19,公差为-2的等差数列,Sn为｛an｝的前n项和,
已知公差不为0的等差数列{An}的首项A1=1,前n项和为Sn,若数列{Sn/An}是等差数列,求An?
已知等差数列an的公差为d,前n项和Sn＝－n^2,则通项公式为
已知等差数列{an}的首项为4,公差为4,其前n项和为Sn,则数列{1/Sn}的前n项和为
设等差数列{an}公差d是2,前n项和为Sn,则lim(an^2-n^2)/Sn
设等差数列{an}公差d是2,前n项和为Sn,则lim(an^2-n^2)/Sn
数列前n项和为sn,a1=1,an+sn是公差为2的等差数列,求an-2是等比数列,并求sn
等差数列An的首项为a1等于3公差等于2前n项和为Sn求数列.1/Sn的前n项和Tn
设数列{an}的前n项和为Sn,若{an}和{根号sn+n}都是公差为d的等差数列,则a1=
谢谢）在等差数列{an}中,设公差为d,若前n项和Sn=-n²;,则{an}的通项公式和公差分别
设公差为d的等差数列{an}的前n项和为Sn,若a1=1,-2/17
等差数列｛an｝前n项和为Sn,且Sn=3n^2+n 求公差d
已知等差数列an中a1=2,其前n项和sn,若数列｛Sn/n｝构成一个公差为2的等差数列,则a3=?