To simplify the expression \( x^{1/6} \cdot x^{1/6} \), we can use the property of exponents that states \( a^m \cdot a^n = a^{m+n} \).
So, we have:
\[ x^{1/6} \cdot x^{1/6} = x^{(1/6 + 1/6)} = x^{2/6} = x^{1/3} \]
The expression \( x^{1/3} \) is equivalent to \( \sqrt[3]{x} \) (the cube root of \( x \)).
Now, looking at the provided responses:
- \( x^{- \sqrt{3}} \)
- \( \frac{1}{\sqrt[3]{x}} \)
- \( x^{- \sqrt{36}} \)
- \( \sqrt[3]{x} \)
The equivalent expression to \( x^{1/3} \) from the options given is \( \sqrt[3]{x} \).
Thus, the correct response is:
\( \sqrt[3]{x} \).