[tex]dane:\\\lambda = 2 \ m\\v = 6\frac{m}{s}\\szukane:\\T = ?\\f = ?\\\\\\v = \frac{\lambda}{T} \ \ /\cdot T\\\\T\cdot v = \lambda \ \ /:v\\\\T = \frac{\lambda}{v}\\\\T = \frac{2 \ m}{6\frac{m}{s}}\\\\\boxed{T = \frac{1}{3} \ s \approx 0,3 \ s}\\\\\\f = \frac{1}{T}\\\\f = \frac{1}{\frac{1}{3} \ s}\\\\\boxed{f = 3 \ Hz}[/tex]
