tana6的知识精选

若{an}为等差数列,Sn是其前n项和,且S11=,则tana6的值为(  )A.              ...
问题详情:若{an}为等差数列,Sn是其前n项和,且S11=,则tana6的值为()A.                                 B.- C.±                              D.-【回答】...
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