等比数列Bn,B5+B6=B7-B5=48,求S10=?答案是1023

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等比数列Bn,B5+B6=B7-B5=48,求S10=?答案是1023

等比数列Bn,B5+B6=B7-B5=48,求S10=?答案是1023
等比数列Bn,B5+B6=B7-B5=48,求S10=?答案是1023

等比数列Bn,B5+B6=B7-B5=48,求S10=?答案是1023
B5+B6=B7-B5=48
则有B5+B5Q=B5Q^2-B5
解得B5=16 Q=2
则A1=1
等比求和公式S10=1023
Sn=[A1(1-q^n]/(1-q)