1. The problem statement, all variables and given/known data The problem along with its detailed solution are attached. 2. Relevant equations Inequality, infinite summation and improper integral. 3. The attempt at a solution I'm following the solution but I can't justify the first (and only) less-than-or-equal sign. Why is that sum less-than-or-equal to that integral? Also, to be picky, when they say two-decimal place accuracy, shouldn't that mean error <= 5/10^3 instead of error < 5/10^3? Whether I am right or wrong, please tell me why. Any input would be greatly appreciated! Thanks in advance!