若cOs(兀⼀6十a)=一1⼀3,则Sin(2兀⼀3十a)的值的

2025-03-26 02:22:04
推荐回答(1个)
回答1:

解:
cos(π/6 +α)=-⅓
sin(2π/3 +α)
=sin[π-(2π/3+α)]
=sin(π/3 -α)
=cos[π/2-(π/3-α)]
=cos(π/6 +α)
=-⅓