求详细过程!

2025-01-01 05:38:10
推荐回答(2个)
回答1:


回答2:

(1)两倍角公式cos²x-sin²x=cos2x2sinxcosx=sin2xf(x)=√3(cos²x-sin²x)+2sinxcosx=√3cos2x+sin2x=2[(√3/2)cos2x+(1/2)sin2x]=2[sin(π/3)cos2x+cos(π/3)sin2x]根据两角和公式sin(A+B)=sinAcosB+cosAsinBf(x)=2sin(2x+π/3)根据sin函数的图像当2kπ-π/2≤2x+π/3≤2kπ+π/2时,k∈Z,f(x)单调递增得x∈[kπ-5π/12,kπ+π/12],k∈Z,f(x)单调递增。(2)令f(x)=12sin(2x+π/3)=1sin(2x+π/3)=1/2得2x+π/3=2kπ+π/6或者2kπ+5π/6,k∈Zx=kπ-π/12或者x=kπ+π/4,k∈Z因为f(a)=1,且a∈[0,π]所以当k=1时,x=11π/12k=0时,x=π/4这两个值符合。所以a=11π/12或者π/4