{an}为等比数列,若a1+a2+a3=26,a4-a1=52,求an
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{an}为等比数列,若a1+a2+a3=26,a4-a1=52,求an
![{an}为等比数列,若a1+a2+a3=26,a4-a1=52,求an](/uploads/image/z/7659317-29-7.jpg?t=%7Ban%7D%E4%B8%BA%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%2C%E8%8B%A5a1%2Ba2%2Ba3%3D26%2Ca4-a1%3D52%2C%E6%B1%82an)
a1(1+q+q^2)=26...(1)
a1(q^3-1)=52...(2)
(2)除以(1)
q-1=2
q=3
a1=2
an=2*3^(n-1)
a1(q^3-1)=52...(2)
(2)除以(1)
q-1=2
q=3
a1=2
an=2*3^(n-1)
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