Second-order partial derivatives f_xx, f_xy, f_yx, and f_yy — IITM BS previous year questions

Second-order partial derivatives f_xx, f_xy, f_yx, and f_yy is part of Higher-Order Partial Derivatives, Week 11 in Mathematics 2. Prasnya files every IIT Madras BS previous year question from this subtopic here, each one with a worked explanation. Take the whole set as a timed mock and you get accuracy, pacing and per-question analysis back.