求函数f(x)=2sin(2x-π/3)的值域(6/π

问题描述:

求函数f(x)=2sin(2x-π/3)的值域(6/π

6/π≤x≤2π/3?应该是π/6≤x≤2π/3吧?
如果是的话,

令y=2x-π/3,则:f(y)=2siny
此时:x=y/2-π/6,
当x∈[π/6,2π/3],有:y∈[0,π]
对于f(y)=2siny,当y∈[0,π]时,有:f(y)∈[0,1]
所以,对于f(x)=sin(2x-π/3),当x∈[π/6,2π/3]时,有:f(x)∈[0,1]
即所求值域是:0≤f(x)≤1.