3.91: Further trigonometry / calculus

0606/22/O/N/23 © UCLES 2023 [Turn over 3 DO NOT USE A CALCULATOR IN THIS QUESTION. A cylinder has base radius ( ) 2 3 + m and volume ( ) 16 9 3 m3 r + . Find the exact value of its height, giving your answer in its simplest form. [4] 4 Solve the following equations. ( ) ex 1 2 +