等比数列中 A7乘A11等于6.A4加A14等于5.则A20/A10等于几.急

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等比数列中 A7乘A11等于6.A4加A14等于5.则A20/A10等于几.急
等比数列中 A7乘A11等于6.A4加A14等于5.则A20/A10等于几.急

等比数列中 A7乘A11等于6.A4加A14等于5.则A20/A10等于几.急
A7*A11 = (A1 * q^6 )*( A1 *q^10) = A1*q3 * A1*q^13 = A4 *A14 = 6
A4 + A14 = 5
A4 = 2 A14 = 3或者A4=3 A14=2
A20/A10 = (A1*q^19)/(A1*q^9) = q^10 = A14/A4 = 2/3 或者3/2