電卓の背後にあるドップラー効果波長

I want to calculate Wavelength in Behind of a Moving Source(λb)Wave Velocity(v)Source Velocity(us)Source Frequency(f0)
Wave Velocity(v) =	m/s
Source Velocity(us) =	m/s
Source Frequency(f0) =	Hz
Wavelength in Behind of a Moving Source(λb) =	m