$\sqrt{1 \sqrt{1 \sqrt{1 { \sqrt{x}}}}}$
2. The expression can be simplified to $x^{\frac{1}{16}}$, then just differentiate that. Are you sorted now?
3. $\frac{d}{dx}x^{\frac{1}{16}}=\frac{1}{16}x^{\frac{-15}{16}}$