Find the domain and range of the following `f(x)=1+3cos2x`

Explanation

To find the domain and range of the function \( f(x) = 1 + 3 \cos(2x) \), we will follow these steps:

### Step 1: Determine the Domain
The function \( f(x) \) involves the cosine function, which is defined for all real numbers. Therefore, the domain of \( f(x) \) is:

\[ \text{Domain: } x \in \mathbb{R} \]
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