an=a1*q^(n-1),Sn=a1(1-q^n)/(1-q)
2S9=S3+S6,2a1*(1-q^9)=a1(1-q^3)+a1(1-q^6)
2a1*q^9=a1*q^3+a1*q^6
2a10=a4+a7
m+s+t=21
一等比数列,S3,S9,S6成等差数列当am ,as ,at,成等差数列时,求m+s+t
一等比数列,S3,S9,S6成等差数列当am ,as ,at,成等差数列时,求m+s+t
数学人气：443 ℃时间：2020-09-17 02:01:26
优质解答
我来回答
类似推荐
猜你喜欢
- 1i will hire the man__they say is a good english speaker
- 2把2分之1和7分之5和9分之2换成同分母分数.
- 3Would you mind my parking the car in front of your house?=Would you mind __ ___ park the car in front of your house?
- 4there are many people in the picture,aren't there?
- 5物理应用题4 (19 10:36:30)
- 6“比尔盖茨是一个成功的人” 英语怎么说
- 7设函数y=ax+2a+1,当-1≤x≤1时,y的值有正有负,则实数a的范围是多少.
- 8设函数f(x)=向量a点乘向量b,向量a=(cosx,-√3),向量b=(2cosx,sin2x),若f(x)=1+√3,且x属于[-π/3,π/3],求x
- 9P70页 第4大题
- 10已知扇形内切圆半径与扇形半径之比为1：3，则内切圆面积与扇形面积之比为 _．