等比数列{an}的a1=5,a100=150,则a5*a96等于?请写过程
问题描述：
等比数列{an}的a1=5,a100=150,则a5*a96等于?请写过程
答
a5*a96=(a4*q)*(a97/q)
=a4*a97
=a3*a98
=a2*a99
=a1*a100
=5*150 =750
答
a1*a100=a50^2=a5*a96=5*150=750