已知函数f(x)=2sin(3-π/3),x∈R

问题描述:

已知函数f(x)=2sin(3-π/3),x∈R
(1)求f(x)单调区间
(2)若x∈[0,π/2],求f(x)的值域

f(x)=2sin(3x-π/3),x∈R对于sinx的单调增区间是(2kπ-π/2,2kπ+π/2)所以2kπ-π/2≤3x-π/3≤2kπ+π/22kπ/3-π/18≤x≤2kπ/3+5π/18单调增区间区间(2kπ/3-π/18,2kπ/3+5π/18)单调减区间也是同上的方法...能详细说下π/2吗?我说的这个π/2是指的3x-π/3=π/2,即 x=5π/18因为π/2包含在【-π/3,7π/6】区间嘛2怎么算出来的?当3x-π/3=π/2时,那么sin(3x-π/3)=1,那么2sin(3x-π/3)=2