30 Highest-Yield Error-Prone Questions

These 30 questions were hand-selected because they sit at the exact points where Korean AA HL students most often lose marks: sign errors in the ambiguous case, forgetting a branch of a trig solution, mixing up asymptotes with holes, misapplying angle-between-line-and-plane, and arithmetic slips inside implicit differentiation. Every numeric answer below was verified independently with SymPy using two different solution methods before being placed in this exam.

Work every question honestly before selecting an answer — once you choose, the choice locks and the full explanation appears immediately below it.