1. The problem is to find the value of $\cos x$ or understand the function $\cos x$. 2. The cosine function, $\cos x$, is a trigonometric function that gives the ratio of the adjacent side to the hypotenuse in a right triangle. 3. The function $\cos x$ is periodic with period $2\pi$, meaning $\cos(x + 2\pi) = \cos x$. 4. The range of $\cos x$ is $[-1,1]$, so $\cos x$ always lies between $-1$ and $1$. 5. If you want to evaluate $\cos x$ for a specific value of $x$, you substitute that value into the function. 6. For example, $\cos 0 = 1$, $\cos \frac{\pi}{2} = 0$, and $\cos \pi = -1$. 7. Without a specific value for $x$, $\cos x$ remains as the function itself. Final answer: $\cos x$ is the cosine function with values between $-1$ and $1$ depending on $x$.