设等比数列an的公比q=2,前n项和为sn,则s4除以a2=

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设等比数列an的公比q=2,前n项和为sn,则s4除以a2=

设等比数列an的公比q=2,前n项和为sn,则s4除以a2=
设等比数列an的公比q=2,前n项和为sn,则s4除以a2=

设等比数列an的公比q=2,前n项和为sn,则s4除以a2=
S4=a1(1-2^n)/(1-2)=a1(2^n-1)
a2=a1*2
S4/a2=(2^n-1)/2