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)