To use the Negative Exponent Rule, we start with the expression \( 3^{-1/2} \).
The Negative Exponent Rule states that \( a^{-n} = \frac{1}{a^n} \). Thus, we can rewrite \( 3^{-1/2} \) as:
\[ 3^{-1/2} = \frac{1}{3^{1/2}} \]
Now, \( 3^{1/2} \) is the square root of 3, which can be written in radical form as \( \sqrt{3} \). Therefore:
\[ 3^{-1/2} = \frac{1}{\sqrt{3}} \]
So the final answer in radical form is:
\[ 3^{-1/2} = \frac{1}{\sqrt{3}} \]