若函数y=Asin(wx+φ)(A>0,w>0,|φ|

问题描述:

若函数y=Asin(wx+φ)(A>0,w>0,|φ|

Asin(wπ/3+φ)=0 (1)
Asin(wπ5/6+φ)=0 (2)
Asin(φ)=2/3 (3)
由(1)cos(wπ/3+φ)=1
由(2)cos(wπ5/6+φ)=-1
cos[(wπ5/6+φ)-(wπ/3+φ)]
=cos(wπ/2)=-1
w=2
由(1):sin(wπ/3+φ)=0
φ=π/3
由(3):A=(2/3)/sin(π/3)=4/9 √3
解析式:y=(4/9)*√3sin(2x+π/3)