y=2cos²x+2√3sinxcosx-1
=cos2x+√3sin2x
=2(1/2cos2x+√3/2sin2x)
=2sin(2x+π/6)
振幅A=2
最小正周期T=2π/2=π
当sin(2x+π/6)=1的时候,y最大值=2
此时2x+π/6=2kπ+π/2
2x=2kπ+π/3
x=kπ+π/6
k为整数
y=2cos²x+2√3sinxcosx-1
=cos2x+√3sin2x
=2(1/2cos2x+√3/2sin2x)
=2sin(2x+π/6)
振幅A=2
最小正周期T=2π/2=π
当sin(2x+π/6)=1的时候,y最大值=2
此时2x+π/6=2kπ+π/2
2x=2kπ+π/3
x=kπ+π/6
k为整数