y = 0.025 cos(125t – 0.37x)y = 0.025 cos(ω t – ω x / v)y = 0.025 cos(ω t – 2π x / λ)角频率 ω = 125 /sω/v = 0.37，波速 v = ω/0.37 = 337.8 m/s2π / λ = 0.37，波长 λ = 2π / 0.37 = 17.0 m
