The Grand Rapids Community College Mathematics Department is very pleased to announce that it will host **two** Mathematics Seminars in April, **both to be presented by current GRCC students**.

**Our first talk: Wednesday, April 15, 3:30-4:30 PM in 102 Cook.**

Gregory Metzner will discuss applications of Trigonometry related to his experience while serving in the United States Marine Corps. The title and abstract of his talk are below.

This talk will focus on using trigonometry to locate positions on a map, and should appeal to anyone with an interest in real-world applications of mathematics. Familiarity with basic trigonometry would be useful, but of course everyone is welcome!

Pop and cookies will be served at 3:15 PM.

**Trigonometry in the Marine Corps**

As a high school student, I did not appreciate math. Upon entering the “real world”, I learned that math is integral and used everywhere, and I found that I can actually learn to enjoy math. As a Marine, I was taught to use basic mathematics on a daily basis. In preparation for a combat deployment, I investigated the mathematical concepts of polar and grid coordinates that could have readily been used, but were not. I wanted an answer as to how I could use math to make my job easier and more efficient. The deeper I investigated, the more dead ends I encountered, and was even told at one point that the type of math I wanted to learn just did not exist. I now know better, and have found the answer to my question. It lies in trigonometry. In my presentation, I will discuss the specific problems I want to solve, and the functions I can use to solve these problems. I will also discuss whether my new found math can actually be employed and used efficiently in the field, compared to the traditional mechanisms in place to solve these problems.

**Our second talk: Thursday, April 16, 3:00-4:00 PM in 103 Cook.**

In this seminar Steven Janke will speak on the historical development and fundamental concepts of Hyperbolic Geometry. See below for the title and abstract.

For more than 2000 years, Euclidean Geometry was considered to be “the” Geometry; there were no others. The discovery of “new” geometries revolutionized mathematics in the 19^{th} century. This talk should be of interest to the curious and open-minded, and, as always, all are welcome!

Pop and cookies will be served at 2:45 PM.

**Triangles, Parallels, and Perpendiculars: A Story of Geometry**

** **One of the basic ideas in geometry is that when you add up all the angles in a triangle you get 180 degrees, but is this always true? Consider the earth and one line being the equator and two other lines being lines of longitude. If we pick two longitudinal lines that are perpendicular then these lines will form a triangle. However, this triangle has 3 right angles which add up to 270 degrees. Surely this must be a mistake, or some special case, or maybe there is something wrong with geometry…or could there possibly be alternative geometries?

Learn about the history of Hyperbolic Geometry, its creation and its discovery, and attempts to prove Euclid’s Parallel Postulate. Some of the major issues with newer geometries are finding logically consistent models, and we will explore some of the famous models for Hyperbolic Geometry and learn some of the basic constructions possible. We will finish with a qualitative investigation into curvature of a surface and what that means for geometry.