Video showing the differential equation has since gone viral, leaving many on social media stumped.
"Dumb as I am, I may as well use my mobile data," wrote Sina Weibo user "sunzhendan."
"I would rather starve," wrote "babazai."
"One super nerd gets it right, and thousands of academic losers are saved," wrote "niuniu" on chouti.com. The hurdles don't stop there. In NAUU's Xinyuan Library Restaurant, a musical riddle challenges students to convert a written eight-note melody to numbered musical notation.
Wi-Fi for nerds only. The canteen of the Nanjing University of Aeronautics and Astronauts offers free Wi-Fi to those who can solve the equation. (The answer to the equation is a six digit number that also serves as the password) pic.twitter.com/KnzEMCmHM3— Chungyan Chow (@ChungyanChow) 10 сентября 2018 г.
"We chose a music notation problem for the Xinyuan Library Restaurant because it has more liberal arts students," said an employee surnamed Ji.
"We chose a math problem for the other cafeteria because it has more engineering students. Many of them have already worked it out," Ji added. For those that can't hack it, Ji said the answer is as easy as Pi.
This article was originally published in Global Times.