19.数列{}满足递推式 (1)求a1.a2.a3, (2)若存在一个实数.使得为等差数列.求值; (3)求数列{}的前n项之和. 解:(1)由 同理求得a2=23, a1=5 查看更多

 

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(文科做)已知数列{an}满足递推式:an-an-1=2n-1,(n≥2,n∈N)且a1=1.
(1)求a2,a3;    
(2)求an;   
(3)若bn=(-1)nan,求数列{bn}的前n项之和Tn

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(文科做)已知数列{an}满足递推式:an-an-1=2n-1,(n≥2,n∈N)且a1=1.
(1)求a2,a3;        
(2)求an;       
(3)若bn=(-1)nan,求数列{bn}的前n项之和Tn

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(文科做)已知数列{an}满足递推式:an-an-1=2n-1,(n≥2,n∈N)且a1=1.
(1)求a2,a3;        
(2)求an;       
(3)若bn=(-1)nan,求数列{bn}的前n项之和Tn

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(文科做)已知数列{an}满足递推式:an-an-1=2n-1,(n≥2,n∈N)且a1=1.
(1)求a2,a3;        
(2)求an;       
(3)若bn=(-1)nan,求数列{bn}的前n项之和Tn

查看答案和解析>>

(文科做)已知数列{an}满足递推式:an-an-1=2n-1,(n≥2,n∈N)且a1=1.
(1)求a2,a3;        
(2)求an;       
(3)若bn=(-1)nan,求数列{bn}的前n项之和Tn

查看答案和解析>>


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