Translations:Sinusoidal waves/62/en

Therefore, ${\rm {|}}kyT{\rm {|}}{\rm {=2}}\pi$. But these are all positive quantities, so $kyT{\rm {=2}}\pi$. As we have just seen, $k{\rm {=2}}\pi {\rm {/}}\lambda$, so ${\rm {2}}\pi vT/\lambda {\rm {=2}}\pi$ from which it follows that $T{\rm {=}}\lambda /v$. The period T is the number of units of time per cycle. The period commonly is expressed in seconds. Thus, the velocity is $v{\rm {=}}\lambda /T$.