设{an}是等差数列{bn}是各项都是正数的等比数列且a1=b1=2,a3+b5=36,a5+b3=14
求(1)数列{an}{bn}的通项公式(2)数列{an|bn}的前n项和Tn
急!!!!!!!!!!!!!!!!!!!!!!!
人气:473 ℃ 时间:2019-08-19 09:01:05
解答
a3+b5=36.Aa5+b3=14.Ba1+4d+b1q^2=142+4d+2q^2=144d+2q^2=122d+q^2=62d=6-q^2.CB-Aa5-a3+b3-b5=-222d+b1q^2-bq^4=-222d+2q^2-2q^4+22=0.D6-q^2+2q^2-2q^4+22=0-2q^4+q^2+28=02q^4-q^2-28=0(2q^2+7)(q^2-4)=0q^2=4 {b...
推荐
- 设{an}是等差数列,{bn}是各项都为正数的等比数列且a1=b1=1,a3+b5=21,a5+b3=13.求[an},{bn}的通项公式,
- 设{an}是等差数列,{bn}是各项都为正数的等比数列,且a1=b1=1,a3+b5=21,a5+b3=13
- 设an是等差数列,bn是各项都为正数的等比数列,且a1=b1=1,a5+b3=13 a3+b5=21
- 设{an}是等差数列,{bn}是各项都为正数的等比数列且a1=b1=1,a3+b5=21,a5+a3=13.求[an},{bn}的通项公式,和求{an/bn}的前n项和Sn
- an是等差数列,bn是各项都为正数的等比数列,且a1+b1=1,a3+b5=19,a5+b3=9.
- I don't like playing basketball这句话对不对
- 一付扑克牌共有54张(包括大王、小王),至少从中取_张牌,才能保证其中必有3种花色.
- 有一架天平,只有5克和35克砝码各一个,现在要把300克的盐分成三等份,问最少要用天平称几次.
猜你喜欢