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等比数列a9乘a10乘a11乘a12=64a6乘a13=

题目详情
等比数列a9乘a10乘a11乘a12=64 a6乘a13 =
▼优质解答
答案和解析
a4*a5*a6*a7*a8*a9*a10=128(a4*a10)*(a5*a9)*(a6*a8)*a7=128a4*a10=a1*q3次方*a1*q9次方=a1*q6次方*a1*q6次方=a7*a7同理:a5*a9=a7*a7a6*a8=a7*a7a7*a7*a7*a7*a7*a7*a7=128a7=21/2a7=1