1{an}正项等比数列且a2a4+2a3a5+a4a6=25则a3+a5=___ 2等比数列{an}中a3-a1=8 a6-a4=216 且Sn=40则n=___ 3等比数列{an}a2=6 a5=162 求{an}的同项公式____ 求证Sn*(Sn+2)/(Sn*Sn) +1<1 4等比数列{an}的前n项
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![1{an}正项等比数列且a2a4+2a3a5+a4a6=25则a3+a5=___ 2等比数列{an}中a3-a1=8 a6-a4=216 且Sn=40则n=___ 3等比数列{an}a2=6 a5=162 求{an}的同项公式____ 求证Sn*(Sn+2)/(Sn*Sn) +1<1 4等比数列{an}的前n项](/uploads/image/z/15241168-64-8.jpg?t=1%EF%BD%9Ban%EF%BD%9D%E6%AD%A3%E9%A1%B9%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%E4%B8%94a2a4%2B2a3a5%2Ba4a6%3D25%E5%88%99a3%2Ba5%3D___+2%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%EF%BD%9Ban%EF%BD%9D%E4%B8%ADa3-a1%3D8+a6-a4%3D216+%E4%B8%94Sn%3D40%E5%88%99n%3D___+3%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%EF%BD%9Ban%EF%BD%9Da2%3D6+a5%3D162+%E6%B1%82%7Ban%7D%E7%9A%84%E5%90%8C%E9%A1%B9%E5%85%AC%E5%BC%8F%EF%BC%BF%EF%BC%BF%EF%BC%BF%EF%BC%BF+%E6%B1%82%E8%AF%81Sn%2A%28Sn%2B2%29%2F%28Sn%2ASn%29+%2B1%EF%BC%9C1+4%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%EF%BD%9Ban%EF%BD%9D%E7%9A%84%E5%89%8Dn%E9%A1%B9)
1{an}正项等比数列且a2a4+2a3a5+a4a6=25则a3+a5=___ 2等比数列{an}中a3-a1=8 a6-a4=216 且Sn=40则n=___ 3等比数列{an}a2=6 a5=162 求{an}的同项公式____ 求证Sn*(Sn+2)/(Sn*Sn) +1<1 4等比数列{an}的前n项
1{an}正项等比数列且a2a4+2a3a5+a4a6=25则a3+a5=___
2等比数列{an}中a3-a1=8 a6-a4=216 且Sn=40则n=___
3等比数列{an}a2=6 a5=162 求{an}的同项公式____
求证Sn*(Sn+2)/(Sn*Sn) +1<1
4等比数列{an}的前n项和为Sn.且S3+S6=2S9.求公比q
5 等差数列 2 3 6 项顺次成等比数列.-9.b1.b2.b3.-1的5个实数成等比数列,则公比q=_____
6已经-9.a1.a2.-1 4个实数成等差数列.-9.b1.b2.b3.-1 五个数成等比数列.则b2(a2-a1)=___
1{an}正项等比数列且a2a4+2a3a5+a4a6=25则a3+a5=___ 2等比数列{an}中a3-a1=8 a6-a4=216 且Sn=40则n=___ 3等比数列{an}a2=6 a5=162 求{an}的同项公式____ 求证Sn*(Sn+2)/(Sn*Sn) +1<1 4等比数列{an}的前n项
1 .正项 a2a4=a3a3 ,a4a6=a5a5
a2a4+2a3a5+a4a6=(a3+a5)^2=25 =>a3+a5=5
2.a3=q^2a1,a6=q^2a4
a1(q^2-1)=8,a4(q^2-1)=216 =>a4/a1=27
a4=q^3a1 =>q=3 ,a1=1
同项公式an=3^(n-1)
3.a5=q^3a2 =>162=6q^3 => q=3,a1=2
an=2*3^(n-1)
好多哈~让后来人接着做`
我要睡拉`