What is the Analogous of Theta in Waves?

[Jhenrique]

I want you note this comparation:
$$\\ \sin(\theta)=\sin(\omega t)=\sin(2\pi f t)=\sin\left(\frac{2\pi t}{T}\right) \\ \\ \sin(?)=\sin(k x)=\sin(2\pi \bar{\nu} x)=\sin\left(\frac{2\pi x}{\lambda}\right)$$
ω is rate of change of θ with respect to t. So, exist a physic/mathematical quantity that when derived with respect to x results the quantity k?

 

[SteamKing]

k is usually used to denote the wave number:

http://en.wikipedia.org/wiki/Wavenumber

 

[Jhenrique]

kx is equal to which quantity?

 

[SteamKing]

The wave number k = 2π / λ

 

[Jhenrique]

Wavenumber is the analogous of omega. I'm asking by analogous of theta.