To rewrite the cosine function \( f(x) = \cos\left(\frac{1}{3}x - \frac{\pi}{6}\right) \) as a translated sine function, we can use the relationship between sine and cosine:
\[ \cos(x) = \sin\left(x + \frac{\pi}{2}\right) \]
Using this relationship, we first rewrite \( f(x) \):
\[ f(x) = \cos\left(\frac{1}{3}x - \frac{\pi}{6}\right) \]
Now, we can express the cosine function in terms of the sine function:
\[ f(x) = \sin\left(\left(\frac{1}{3}x - \frac{\pi}{6}\right) + \frac{\pi}{2}\right) \]
To combine the arguments, we have:
\[ f(x) = \sin\left(\frac{1}{3}x - \frac{\pi}{6} + \frac{\pi}{2}\right) \]
Now, we need to find a common denominator for the terms inside the sine function. The angle \( \frac{\pi}{2} \) can be expressed as \( \frac{3\pi}{6} \):
\[ -\frac{\pi}{6} + \frac{3\pi}{6} = \frac{2\pi}{6} = \frac{\pi}{3} \]
Therefore, we can rewrite our function as:
\[ f(x) = \sin\left(\frac{1}{3}x + \frac{\pi}{3}\right) \]
Thus, the cosine function \( f(x) = \cos\left(\frac{1}{3}x - \frac{\pi}{6}\right) \) can be rewritten as the translated sine function:
\[ f(x) = \sin\left(\frac{1}{3}x + \frac{\pi}{3}\right) \]