设数列an为等差数列,数列bn为等比数列若a1

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/15 18:35:06
设数列an为等差数列,数列bn为等比数列若a1
xS=N0G[v"Q"%p"V '`8 =MCdײjtx9\tsz=h8>:]|1$}EׂUTg <آ ujZ.iB3"Rt9GF{+Q 1N,P9h H.^ ǖ)YrŖO6  4 γ4-90YX>Ozz=o/&\RL 5@/le̒ʯw|T(

设数列an为等差数列,数列bn为等比数列若a1
设数列an为等差数列,数列bn为等比数列若a1

设数列an为等差数列,数列bn为等比数列若a1
a(n) = a + (n-1)d,
a = a(1) < a(2) = a + d,d>0.
b(n) = bq^(n-1) = [a(n)]^2 >=0.
b = b(1) < b(2) = bq,b>0,q>1.
b = b(1) = [a(1)]^2 = a^2,
b(n) = a^2q^(n-1).
b(2) = a^2q = [a(2)]^2 = [a+d]^2,q = [1 + d/a]^2.
b(n) = a^2[1+d/a]^(2n-2)
b(3) = a^2[1+d/a]^4 = [a(3)]^2 = [a+2d]^2,
[1+d/a]^4 = [1+2d/a]^2,
0 = [(1+d/a)^2 - (1+2d/a)][(1+d/a)^2 + (1+2d/a)]
= [1 + 2d/a + (d/a)^2 - 1 - 2d/a][1+2d/a + (d/a)^2 + 1 + 2d/a]
= (d/a)^2[(d/a)^2 +4d/a + 2],
0 = (d/a)^2 + 4(d/a) + 4 - 2 = [d/a+2]^2 - 2 = [d/a+2+2^(1/2)][d/a+2-2^(1/2)],
0 = d/a + 2 + 2^(1/2)或0 = d/a + 2-2^(1/2).
q = [1+d/a]^2 = [1+2^(1/2)]^2 = 3 + 2^(3/2),

q = [1+d/a]^2 = [1-2^(1/2)]^2 = 3 - 2^(3/2)

设数列an为等差数列,数列bn为等比数列若a1 设数列an为等差数列,数列bn为等比数列若a1 设数列(an)为等差数列,数列(bn)为等比数列,若a1 设数列{an}是等比数列,bn=an+an+1,问{bn}是否为等比数列 数列{an} 是首项为0的等差数列,数列{bn} 是首项为1的等比数列,设cn=an+bn,数列{cn} 的前三项依次为1,1,2,求数列{an} 、{bn} 的通项公式; 如果数列{an}是等差数列,设bn=(1/2)^an,数列{bn}是等比数列吗? 已知数列{an}是首项为a1=1/4,公比q=1/4的等比数列,设bn+2=3(log1/4)an(n∈N*),数列{Cn}满足Cn=an*bn求证:数列bn成等差数列 设各项均为正数的数列{an}和{bn}满足:an,bn,an+1成等差数列,bn,an+1,bn+1等比数列且a1=1,b1=2,a2=3求通项an,bn 设各项均为正数的数列{an}和{bn}满足:an,bn,an+1成等差数列,bn,an+1,bn+1成等比数列,且a1=1,b1=2,a2=3,求通项an,bn 已知数列{an}是公差为正数的等差数列,数列{bn}是首相为1的等比数列,设cn=an×bn,且数列﹛cn﹜的前三项依为1,4,12.﹙1﹚求数列{an},{bn}的通项公式;﹙2﹚若数列{an}的前n项和为Sn,求数列﹛Sn/n﹜ 设等差数列{an}的公差d≠0,数列{bn}为等比数列,若a1=b1,b2=a3 b3=a2,则bn的公比为 若数列{Cn}={An}*{Bn},{An}为等差数列,{Bn}为等比数列求{Cn}的和Sn 设数列{an}{bn}满足a1=b1=6 a2=b2=4 a3=b3=3若{an+1 - an}为等差数列.{bn+1 -bn}为等比数列.分别求{an}{bn}的通项公式. 已知等差数列{an}的前四项和为10,且a2,a3,a7成等比数列.(1)求通项公式an.(2)设bn=2^an,求数列bn...已知等差数列{an}的前四项和为10,且a2,a3,a7成等比数列.(1)求通项公式an.(2)设bn=2^an,求数列bn的前n 已知数列3,7,13,…的各项是由一个等比数列和一个等差数列的对应项相加得到的其中等差数列的首项为1,记等比数列为数列{an},等差数列为{bn}(1)求数列{an},{bn}的通项公式an,bn(2)设Tn=b1/a1+b2/b2+…+b 已知数列{an},{bn}满足a1=2,2an=1+2an*an+1,设{bn}=an-1求数列{1n}为等差数列急!!! 已知等比数列{bn}是公比为q与数列{an}满足bn=3^an,(1)证明数列{an}是等差数列 (2)若b8=3,且数列{an}...已知等比数列{bn}是公比为q与数列{an}满足bn=3^an,(1)证明数列{an}是等差数列 (2)若b8=3,且数列{an}的 数列{an}是首项为1的等差数列,数列{bn}是首项为1的等比数列,设Cn=anbn,且数列{Cn}的前三项为1,4 ,121求数列{an}{bn}的通项公式2若等差数列{an}的公差d>0,他的前n项和为Sn,求数列{Sn/n}的前n项和Tn3若等