343?lne4?ln4e?ln3411332.7?ln419.68 ?ln2?4?2?(ln2?4)n?n?12?n?22
1111ln(1?)?ln(1?）?ln(1?)?????ln(1?)??123nn?2n2
（1?
?11)(1?12)(1?13)....(1?1nn?2)?e21、（14分）（1）证明：an?1?can?1?can?1?1?c(an?1) a?1时，{an-1}等比数列。a1?1?a?1?an?1?(a?1)cn?1?an?(a?1)cn?1?1 n11n?11n?b?n() ()?1??(）?1（2）由（1）的an??1 n2222由错位相减法得Sn（3）Cn?4??2?5nn?22n
(?4)?1nn
dn?25?16n(16?1)(16?4)?25?16n2nn(16）?3?16?41162?116325?16(16)nn2?1162516n
25?(1?())161611n1?Tn?d1?d2?????dn?25(16???????)?n1?116?5(1?3116)?n53
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