=1×2×3×.×n, 设数列{an}有,an=㏒(n=1) 2009!,1/a1+1/a2+.+1/a2008=?
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![=1×2×3×.×n, 设数列{an}有,an=㏒(n=1) 2009!,1/a1+1/a2+.+1/a2008=?](/uploads/image/z/1695131-35-1.jpg?t=%3D1%C3%972%C3%973%C3%97.%C3%97n%2C%26%23160%3B+%E8%AE%BE%E6%95%B0%E5%88%97%7Ban%7D%E6%9C%89%2Can%3D%E3%8F%92%28n%3D1%29+2009%21%2C1%EF%BC%8Fa1%2B1%EF%BC%8Fa2%2B.%2B1%EF%BC%8Fa2008%3D%3F)
=1×2×3×.×n, 设数列{an}有,an=㏒(n=1) 2009!,1/a1+1/a2+.+1/a2008=?
=1×2×3×.×n, 设数列{an}有,an=㏒(n=1) 2009!,1/a1+1/a2+.+1/a2008=?
=1×2×3×.×n, 设数列{an}有,an=㏒(n=1) 2009!,1/a1+1/a2+.+1/a2008=?
an=lg2009!/lg(n+1)
1/an=lg(n+1)/lg2009!
原式=lg(1+1)/lg2009!+lg(2+1)/lg2009!+……+lg(2008+1)/lg2009!
=lg(2×3×……×2009)/lg2009!
=lg2009!/lg2009!
=1
你的题目出的不懂。