Solve question step by step

Give the best big-Oh characterization for each of the following running time estimates (where n is the size of the input problem). a 37 + x log x^2 + 3000 log x b. n + (n - 1) + (n - 2) + .. + 3 + 2 + 1 c. 1000n^2 + 16n + 3^n d. 3^8 + 2^12 What is the value of following sum, where S = {1, 3, 5, 7, 9}? You do not need to solve it just show the formula is enough. sigma_i elementof S (1/i)