• 计算:(1)(π)0+(279)0.5+0.1-2+(21027) -23+3748;(2)12lg3249-43lg√8+lg√245.试题及答案-解答题-云返教育

    • 试题详情

      计算:
      (1)(π)
      0+(2
      7
      9
      0.5+0.1-2+(2
      10
      27
      -
      2
      3
      +
      37
      48

      (2)
      1
      2
      lg
      32
      49
      -
      4
      3
      lg
      8
      +lg
      245

      试题解答


      见解析
      解:(1)(π)0+(2
      7
      9
      0.5+0.1-2+(2
      10
      27
      -
      2
      3
      +
      37
      48

      =1+(
      5
      3
      )2×0.5+
      1
      0.12
      +(
      4
      3
      )3×(-
      2
      3
      )
      +
      37
      48

      =1+
      5
      3
      +100+
      9
      16
      +
      37
      48

      =101+3=104;
      (2)
      1
      2
      lg
      32
      49
      -
      4
      3
      lg
      8
      +lg
      245

      =
      1
      2
      lg32-
      1
      2
      lg49-
      4
      3
      ×
      1
      2
      lg8+
      1
      2
      lg245
      =
      5
      2
      lg2-lg7-2lg2+
      1
      2
      lg245
      =
      1
      2
      lg2+
      1
      2
      lg245-lg7
      =
      1
      2
      lg490-lg7
      =lg7+
      1
      2
      -lg7
      =
      1
      2
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