The image contains parts of mathematical expressions. Based on what I can discern:

1. (iii) appears to involve the term $4 (\sin \sqrt{5})$.
2. (iv) appears to involve an inverse cosine function, likely: $\cos^{-1} \left( \frac{\sqrt{6} + 1}{2\sqrt{3}} \right) - \frac{\pi}{6}$

Would you like a step-by-step solution for either or both of these? Let me know how I can assist further.

Questions to Expand:

1. What are the specific instructions for solving $4 (\sin \sqrt{5})$?
2. Do you want a detailed calculation of $\cos^{-1} \left( \frac{\sqrt{6} + 1}{2\sqrt{3}} \right)$?
3. Should I simplify any expressions further?
4. Would you like an explanation of how the inverse trigonometric functions work?
5. Are there any specific constraints or contexts for these problems?

Tip: When working with inverse trigonometric functions, always check if the result lies within the principal branch (range) of the function.