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关于B.等于的百科

若m·23=26,则m等于( )  A.2             B.4            C.6   ...
若的值等于(  )   A.2          B.3          C.4         D.6
设*等于A.{1,2,3}      B.{1,2,4}      C.{1,3,4}      D.{1,...
设f(x)=,且f(2)=4,则f(﹣2)等于(  )A.1    B.2     C.3    D.4
  • 设f(x)=,且f(2)=4,则f(﹣2)等于(  )A.1    B.2     C.3    D.4

  • 问题详情:设f(x)=,且f(2)=4,则f(﹣2)等于()A.1    B.2     C.3    D.4【回答】C【考点】函数的值.【分析】由已知得f(2)=a2=4,由a是对数的底数,得a=2,由此能求出f(﹣2).【解答】解:∵f(x)=,且f(2)=4,∴f(2)=a2=4,解得a=±2,∵a是对数的底数,∴a≠﹣2,∴a=2,∴f(﹣2)=log2(4+4)=3.故选:C.【点评】本题考查函数值的...
  • 27811
若,则等于(     )A.8                          B.9           ...
若分式的值为0,则x的值等于(  )A.0                       B.2        ...
若分式的值为0,则的值等于A.0                             B.3       ...
若a·23=26,则a等于   A.2           B.4               C.6    ...
等于(  )A.0                        B.C.1                 ...
若,,则的值等于(  )A.5                          B.1           ...
等于                      A.-            B.-             ...
等于(  ) A.0                            B.               ...
等于(   )A.  B.  C.  D.
+等于(  )A.lg3       B.-lg3C.            D.-
若,则等于A.                           B.                   ...
cos(-)等于(  )A.             B.             C.-          ...
等于(  )A.       B.            C.               D.
.等于(   )A.                B.                C.         ...
等于(  )A.﹣  B.   C.﹣      D. 
  • 等于(  )A.﹣  B.   C.﹣      D. 

  • 问题详情:等于()A.﹣  B.   C.﹣      D.【回答】B【考点】运用诱导公式化简求值;根式与分数指数幂的互化及其化简运算.【专题】计算题;转化思想;三角函数的求值.【分析】由sin120°>0,去掉根号,利用诱导公式即可化简求值.【解答】解:=sin120°=sin60°=.故选:B.【点评】本题主要考查...
  • 25625
若,则等于     (           )      A.         B.             ...
等于 A.2                                           B.-2  ...
等于(  )A.-       B.         C.    D.-
等于( )A.   B.    C.    D.
等于(  )A.     B.   C.  D.
 等于(  )A.    B.     C.     D.