4) -1/2
1) Rewriting the expression:
[tex]\frac{1}{\sqrt[]{x}}[/tex]2) As a power we can write this way, considering that we can rewrite any radical as a power and that when we have a radical on the denominator we can rewrite it as a negative rational exponent. So we can write it out:
[tex]\frac{1}{\sqrt[]{x}}=\frac{1}{x^{\frac{1}{2}}}=x^{-\frac{1}{2}}[/tex]3) Hence, the answer is 4) -1/2