有如下公式，如果我没记错的话
sin(a)sin(b)=-1/2*[cos(a+b)-cos(a-b)]
cos(a)cos(b)=1/2*[cos(a+b)+cos(a-b)]
sin(a)cos(b)=1/2*[sin(a+b)+sin(a-b)]
原式
=1/2*[sin(7π/12-6x)+sin(-π/12)]+1/2*[cos(7π/12)-cos(6x-π/12)]
=1/2sin(7π/12-6x)+1/2cos(7π/12)+1/2cos(7π/12)-1/2sin(7π/12-6x)]
=cos(7π/12)
若化为算式
=cos(60+45)
=cos60cos45-sin60sin45
=（根号下2-根号下6）/4
内容全部来源于网络收集，如有侵权，请联系网站删除：QQ：24596024