Observe the following recurrences, use master theorem to solve those that can be solved(Please indicate which case). For those that cannot be solved directly, try to devise some guess of the solution, and then use substitution method to prove your guess.

a) T(n)=4T(n/3)+nlg⁡n.

b) T(n)=4T(n/2)+n^2 √n.

c) T(n)=T(n/2)+T(n/4)+T(n/8)+n.

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2