ab=3cos(x/3)cos(x/6)-3sin(x/3)sin(x/6) =3cos(x/3+x/6)=3cos(x/2) f(x)=1/2*3cos(x/2)+(3√3/2)sin(x/2) =3(1/2cos(x/2)+√3/2sin(x/2)) =3cos(x/2-π/3)
f(x)=3cos(x/2-π/3)
f(x)=3cos(x/2-π/3)
求的ab=3cos(x/3)cos(x/6)-3sin(x/3)sin(x/6) =3cos(x/3+x/6)=3cos(x/2) 代入函数f(x)=1/2ab+（3√3/2）sinx/2. 可得结果f(x)=（3/2）cos(x/2)+(3√3/2)sin(x/2) =3(1/2cos(x/2)+√3/2sin(x/2)) =3cos(x/2-π/3)
那个对号是什么意思？
答：a=(2sinx,cosx),b=(√3cosx.cosx) F(x)=a·b-1 =2√3sinxcosx+2(cosx)^2-1 =√3sin2x+cos2...详情>>
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