已知函数f(x)=Asin(2ωx+φ)(x∈R,ω>0,0
问题描述:
已知函数f(x)=Asin(2ωx+φ)(x∈R,ω>0,0
答
已知函数f(x)=Asin(2ωx+φ)(x∈R,ω>0,0求函数f(x)的解析式若把函数f(x)的图像向右平移π/4个单位得到函数g(x)的图像,求函数g(x)在区间[-π/6,π/4]上的最值及相应x的值
(1)解析:由图知T/2=11π/12-5π/12=π/2==>T=π==>2ω=2==>ω=1
所以,f(x)=Asin(2x+φ) 图中未标识最值,不仿设A=2
f(0)=Asin(φ)=1==>φ=arcsin(1/A)=π/6
把函数f(x)的图像向右平移π/4个单位得到函数g(x)的图像
g(x)=Asin(2x-π/2+φ)=2sin(2x-π/3)
单调增区间:2kπ-π/2kπ-π/12因为在区间[-π/6,π/4]上
g(-π/12)=2sin(-π/6-π/3)=-2
g(π/4)=2sin(π/2-π/3)=1
所以,在区间[-π/6,π/4]上最小值g(-π/12)=-2,最大值为g(π/4)=1