求数列{an}{bn}满足a1=1,a2=r,r>0,bn=ana(n+1)且{bn}是公比为q的等比,设Cn=a (2n-1)+a2n(1)求{an}通项(2)设dn=lgC(n+1)/lgCn,求{dn}最大项与最小项的值r=2的19.2次方-1,q=1/2

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求数列{an}{bn}满足a1=1,a2=r,r>0,bn=ana(n+1)且{bn}是公比为q的等比,设Cn=a (2n-1)+a2n(1)求{an}通项(2)设dn=lgC(n+1)/lgCn,求{dn}最大项与最小项的值r=2的19.2次方-1,q=1/2
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求数列{an}{bn}满足a1=1,a2=r,r>0,bn=ana(n+1)且{bn}是公比为q的等比,设Cn=a (2n-1)+a2n(1)求{an}通项(2)设dn=lgC(n+1)/lgCn,求{dn}最大项与最小项的值r=2的19.2次方-1,q=1/2
求数列{an}{bn}满足a1=1,a2=r,r>0,bn=ana(n+1)且{bn}是公比为q的等比,设Cn=a (2n-1)+a2n
(1)求{an}通项
(2)设dn=lgC(n+1)/lgCn,求{dn}最大项与最小项的值
r=2的19.2次方-1,q=1/2

求数列{an}{bn}满足a1=1,a2=r,r>0,bn=ana(n+1)且{bn}是公比为q的等比,设Cn=a (2n-1)+a2n(1)求{an}通项(2)设dn=lgC(n+1)/lgCn,求{dn}最大项与最小项的值r=2的19.2次方-1,q=1/2
b1 = a1a2 = r,故bn = r*q^(n-1)
又b(n+1)/bn = a(n+1)*a(n+2)/(an*a(n+1)) = a(n+2)/an、b(n+1)/bn = q
可得当n为奇数时an = a1*q^((n+1)/2 - 1) = q^((n-1)/2)
当n为偶数时an = a2*q^(n/2 - 1) = r*q^(n/2 - 1)
cn = a(2n-1)+a2n = q^(n-1) + r*q^(n-1) = (1+r)*q^(n-1)

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