Concerning a pressure coefficient

[naggy]

On wikipedia it says that the pressure coefficient can be written as

$$C_p = 1 - (V/V_{inf})^2$$

where V is the velocity.

So if I have given a steady velocity field, $$V = (v_x,v_y)$$, does the equation for $$C_p$$ hold for both coordinates or only the speed $$\sqrt{v_x^2+v_y^2}$$ ?

I'm supposed to determine the largest and lowest value for C_p and I don´t know which formula to use.

 

[naggy]

Basically I'm asking if there is such a thing as a pressure coefficient in the x-direction and a pressure coefficient in the y direction?