The results are:
- \( f(1) = 5.0 \)
- \( f(-7) \approx -2.1111 \)
- \( f\left(\frac{1}{2}\right) \approx 2.3333 \)
Thus, the final answers are:
\[
\boxed{f(1) = 5.0}
\]
\[
\boxed{f(-7) \approx -2.1111}
\]
\[
\boxed{f\left(\frac{1}{2}\right) \approx 2.3333}
\]