已知函数fx=2cos二分之x(√3cos二分之x-sin二分之x 设x属于[-90度,

0度]。fx=√3+1求x
2025-06-20 11:25:53
推荐回答(1个)
回答1:

f(x)=2cos(x/2)[√3cos(x/2)-sin(x/2)]=2√3cos²(x/2)-2cos(x/2)sin(x/2)
=√3(1+cosx)-sinx=√3cosx-sinx+√3=2cos(x+π/6)+√3
∵f(x)=√3+1
∴2cos(x+π/6)+√3=√3+1
∴cos(x+π/6)=1/2
又x∈[-π/2,π/2]
∴x+π/6∈[-π/3,,2π/3]
∴x+π/6=-π/3或x+π/6=π/3
∴x=-π/2或x=π/6