求y=sin2x+根号3cos2x的周期和值域

问题描述:

求y=sin2x+根号3cos2x的周期和值域

y=sin2x+根号3cos2x
=2cosπ/6sin2x+cos2xsinπ/6
=2sin(2x+π/6)
所以
周期=π
值域为【-2,2】

y=sin2x+根号3cos2x
=2sin(2x+π/3)
周期T=2π/2=π
和值域 [-2,2]

y=sin2x+√3*cos2x
=2(1/2*sin2x+√3/2*cos2x)
=2sin(2x+π/3)
函数的周期为:T=2kπ/2=kπ,k为整数
∵-1≤sin(2x+π/3)≤1
∴函数的值域为:[-2,2]