Freshmen made a strong showing in the 2015 Northern Illinois University Mathematics Contest, held in late February.

The $100 first prize was won by Tu Nguyen, a freshman **biochemistry** major from Aurora. Nguyen and other contest winners will be recognized Sunday, April 19, at the **Department of Mathematical Sciences**‘ Awards Ceremony and Reception.

The math contest saw a tie for second place between Xiaofu Li, a freshman **accountancy** major from Shijiazhuang, in Hebei Province, China, and Joshua Stevens, a senior from Oswego who is double-majoring in mathematical sciences and **physics**. Each will receive the $75 second prize.

Greg Sassi, a junior mechanical engineering major from Island Lake, took third place and an award of $50. Sassi also finished third in the 2014 contest.

The annual Northern Illinois University Mathematics Contest has a format where freshmen and sophomores have a fair chance to compete with juniors and seniors. The underclassmen have fewer restrictions on their choice of problems to attempt.

The contest is open to all full-time undergraduates at NIU. Each contestant turns in solutions to a choice of six out of 11 problems. Topics this year ranged from high school level number theory, geometry and trigonometry problems through calculus and linear algebra. Professors Harvey Blau, Y. C. Kwong and Deepak Naidu supervised the competition.

One of the elementary-level problems was the following: Let a, b, and c be odd positive integers. Prove that a quadratic polynomial with coefficients a, b, c has no rational root; that is, no root of the form r/s, where r and s can be taken as relatively prime integers.

Here is a problem that required a non-routine application of calculus: Let ln denote the natural logarithm function. Find the limit, as integer n goes to infinity, of the expression (2ln2 + 3ln3 + … + nln n)/(n squared times ln n).

For more information, email blau@math.niu.edu.