I need help with part (b).

3. [4 marks] We Wish to apply the bisection procedure starting from the interval I0 = [110,50] = [0, 2] and using the rule: 0 Choose [H1 to be the lefthand subinterval if k is a multiple of 3, 0 Choose Ik+1 to be the righthand subinterval if k is a not a multiple of 3, Where, as usual, mk is the midpoint of the interval 1;, = [41],, bk]. a) Find :13 and b3. b) What is sup an? (No proof required)