• 若cos(π6-α)=m,则sin(π3+α)= ;cos(5π6+α)= .试题及答案-填空题-云返教育

    • 试题详情

      若cos(
      π
      6
      -α)=m,则sin(
      π
      3
      +α)=          ;cos(
      6
      +α)=         

      试题解答


      m:-m
      解:∵(
      π
      6
      -α)+(
      π
      3
      +α)=
      π
      2
      ,(
      π
      6
      -α)+(
      6
      +α)=π,cos(
      π
      6
      -α)=m;
      ∴sin(
      π
      3
      +α)=sin[
      π
      2
      -(
      π
      6
      -α)]=cos(
      π
      6
      -α)=m;
      cos(
      6
      +α)=cos[π-(
      π
      6
      -α)]=-cos(
      π
      6
      -α)=-m.
      故答案为:m,-m.
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