To simplify the expression \( \frac{5 \frac{1}{2}}{(3^{125})} \), we first need to convert the mixed number \( 5 \frac{1}{2} \) into an improper fraction.
The mixed number \( 5 \frac{1}{2} \) can be converted into an improper fraction as follows:
\[ 5 \frac{1}{2} = \frac{5 \times 2 + 1}{2} = \frac{10 + 1}{2} = \frac{11}{2} \]
Now, we rewrite the given expression:
\[ \frac{5 \frac{1}{2}}{3^{125}} = \frac{\frac{11}{2}}{3^{125}} = \frac{11}{2 \cdot 3^{125}} \]
So, the simplified expression is:
\[ \frac{11}{2 \cdot 3^{125}} \]
Thus, the equivalent expression, when simplified, is \(\frac{11}{2 \cdot 3^{125}}\).