已知函数f(x)=2-sin(2x+π/6)-2sin^2x x∈R 求f(x)的最小正周期记三角型ABC内角A,B,C的对边长分别为a,b,c若F(B/2)=1 b=1 c=√3,a为多少

问题描述:

已知函数f(x)=2-sin(2x+π/6)-2sin^2x x∈R 求f(x)的最小正周期
记三角型ABC内角A,B,C的对边长分别为a,b,c若F(B/2)=1 b=1 c=√3,a为多少

求a的值(3)求在(2)条件下f(x(1)正周期显然为2π/ω=2π/2=(2)单看2sin(2x+π/6)这个函数在(k∈R)

f(x)=1-2sin^2x+1-(sin2x*cosπ/6+cos2x*sinπ/6)
=cos2x-根号三/2sin2x-1/2cos2x+1
=1/2cos2x-根号三/2sin2x+1
=-sin(2x-π/6)+1
T=2π/2=π

f(x)=2-[(√3/2)sin2x+(1/2)cos2x]+(1/2)[1-cos2x]
=(5/2)-(√3/2)sin2x-(3/2)cos2x
=(5/2)-√3[(1/2)sin2x+(√3/2)cos2x]
=(5/2)-√3sin(2x+π/3)
最小正周期是2π/2=π