1. **Problem:** The user requested answers for 1 to 5; we will solve only the first problem. 2. **Formula:** Use the identity function $f(x)=x$ which returns its input unchanged. 3. **Important rules:** To evaluate, substitute the given value into the function and simplify. 4. **Intermediate work:** Substitute $x=1$ into $f(x)=x$ to obtain $f(1)=1$. 5. **Explanation:** This shows that the value at 1 is 1 because the function outputs its input. 6. **Final answer:** $1$.