Category Archives: College Algebra

Regression Using Google Sheets

Like other spreadsheets, Google Sheets may be used to find a regression model for data. Following a few simple steps, we can graph a set of data in a scatter plot and find the corresponding model.

Suppose we have the demand data show in the table below.


To find a linear model for the Average Price per Gallon as a function of the Weekly Demand, we need to make a scatter plot of this data and add the linear regression model to it. Continue reading Regression Using Google Sheets

Passive and Active Activities in the Flipped Classroom (Part 2)

redwood_01I originally planned this post to be about the Verizon Activity I talked about at MAA Mathfest. However, I decided to write about an activity I came up with on my way back from the Mathfest.

I guess all of you are also finishing off your first week or two of classes. Over the years I have spent less and less time going over the course policies on the first day. For me, the first day used to be an anomaly. I talked all of the hour and fifteen minutes and they sat. None of the subsequent classes would be like this. Yet this first day often turns students off and gives them the impression that my class is a one way communication channel. Many students may drop the class purely on the basis of that first day.

Instead of spending the entire class on the syllabus, I do fifteen minutes on how their grade is determined and then move on to an activity. They take a syllabus quiz over everything and that seems to be a better way to get them to review what they will be held responsible for. For my college algebra class this semester, this activity had a secret motive. I decided to add to the group activities I do in class and make the projects in the class a collaborative effort. To make these groups effective, I need to get a feel for the students and how they work together. I wanted the activity to give me a feel for their personality…leader or follower. Continue reading Passive and Active Activities in the Flipped Classroom (Part 2)

Doubling Time on Gilligan’s Island

Populations are often described by their doubling times. The doubling time is the amount of time it takes a population to double. We can calculate the doubling time of an increasing exponential model by examining its graph carefully. Since students seem to enjoy themodel for population growth on Gilligan’s Island, I like to use it to illustrate doubling in an exponential function. Continue reading Doubling Time on Gilligan’s Island

What Should Have Happened on Gilligan’s Island?

Last week the students in my College Algebra started exponential functions. They got started on the basics of exponential graphs, when they are increasing and decreasing, and exponentials with a base e. With these basics completed, they are working on an Applications Quiz this week. To get them started on this material, I introduced an application based on Gilligan’s Island.

Continue reading What Should Have Happened on Gilligan’s Island?

Introducing Piecewise Functions

After weeks of linear functions, quadratic functions, and matrices, I needed an introductory example for piecewise functions. Examples like this catch student’s attention and get them thinking about how math might be used in real life. I used the example below in class and in the form you see below for my online classes.

How many of you have a car? How many of you have car insurance? In most of my classes, almost every student has a car and insurance. Yet many people are completely unfamiliar with how their insurance works and what they pay annually for that insurance.

For most people, the most important part of their insurance is the premium they pay every six months. A typical premium is $600 every 6 months. This premium may vary depending on the deductible amount. The deductible is the amount you must for a claim before the insurance company pays the rest of the claim. A higher deductible typically means a lower premium. Comparatively speaking, a lower deductible means a higher premium.

Continue reading Introducing Piecewise Functions