Skip to main content

Do-Over: Integration Over Regions in the Plane

How I chose which project to repeat and what needs fixed

Over the course of the semester, I've learned a lot about not only explaining math but also the logistics of printing a helpful 3D model. In many of my calculus courses, professors have stood at the chalkboard and tried to draw a 3D object, only for the students to be more confused than before the visual aid was added. When I thought about which project to do again, I tried thinking of a project where my print was difficult to visualize and only made the topic more confusing. My integration over regions in the plane project came to mind.

Originally, I picked the function \(f(x, y) = \frac{1}{3}(x^2)(2y)\) on the plane bounded by \(y = e^{x-5}\) and \(y = ln(x)+5\) from [0, 7] x [0, 7]. This function grows very quickly, which was seen on my model because I picked such a large rectangular region. The print was very tall and super skinny. It was difficult to see the rectangles of the approximation because of this.
To fix this issue, I can do one of two things: 1) I can have the rectangular region enclosed by [0, 1] x [0, 1] so that the steps between x- and y-values are not so drastic, or 2) I can pick a new function. If I make the rectangular region smaller, you will no longer be able to see the shape of the domain, below.
Therefore, I am going to pick a function that does not grow as quickly over the same domain. This way, you'll be able to compare the original function to a better function and how in this new case you can see the details I originally intended for you to see much clearer. (I wanted the domain to have a leaf-like shape for fall, which I still want to celebrate Taylor Swift's new album.)

How I implemented the improvements

I started implementing these changes by first finding a slow-growing function of two variables that wasn't too basic. I ended up choosing \(f(x,y)=\frac{10}{2x+y}\).
As you can see, this function fixes my huge growth issue over the chosen region, and we can still see the shape of the domain. It may be on the less-interesting side of things, but any fancy functions with exponentials, etc. were not great for printing. Here is the model using the rectangular approximation method and right-hand endpoints:
As you can see, the steps are not as extreme, which was my goal. I think this model does a much better job at helping students visualize a rectangular approximation, given you can actually see the rectangles this time. My print is going to be blown up to have about a 3.5 x 3.5 inch base so that you can see everything as clearly as possible.

Word count: 468

Comments

Popular posts from this blog

Do Over: Integration Over a Region in a Plane

Throughout the semester we have covered a variety of topics and how their mathematical orientation applies to real world scenarios. One topic we discussed, and I would like to revisit, is integration over a region in a plane which involves calculating a double integral. Integrating functions of two variables allows us to calculate the volume under the function in a 3D space. You can see a more in depth description and my previous example in my blog post, https://ukyma391.blogspot.com/2021/09/integration-for-over-regions-in-plane_27.html . I want to revisit this topic because in my previous attempt my volume calculations were incorrect, and my print lacked structural stability. I believed this print and calculation was the topic I could most improve on and wanted to give it another chance. What needed Improvement? The function used previously was f(x) = cos(xy) bounded on [-3,3] x [-1,3]. After solving for the estimated and actual volume, it was difficult to represent in a print...

Knot 9-31

Knot 9-31 A knot is mathematics is defined as a closed, non-self-intersecting curve that is placed in three dimensions and cannot be the "unknot". The main difference between a knot in the real world and a known in mathematics is that a knot in mathematics does not contain any extra strands. The example following will help visualize this. Today, I have specifically chosen knot 9-31 from the Knot Atlas. This knot is very unique and contains some very interesting properties that we are going to look into. The Crossing Number For my knot today, I chose knot 9-31 from the Knot Atlas. This knot contains 9 crossings! The Unknotting Number The unknotting number is exactly what is sounds like. This is the minimum number of times the knot must be passed through itself to untie it. Luckily, the Knot Atlas is super useful and provides the unknotting number for us, but I still...

Do Over: Integration for Over Regions in the Plane

Introduction Earlier in the semester, we visited the topic of integration for over region regions in the plane. This was our first experience with taking integration in the third dimension. To do this, we had to use double integrals to calculate the volume of a region between two surfaces. This topic seems relatively straightforward and anyone who has taken a higher calculus class knows of double integrals. Today, we are going to revisit this topic for a couple of reasons. Why Double Integrals Again? As mentioned before, I am revisiting this topic for a couple of reasons. One of the main reasons is due to how the 3D print turned out. Due to the function, I chose, the final rectangular prism was stand alone. When printing, this resulted in a sloppy prism that lacked structural integrity. The image below is a reference to my original design that includes the prism that had the issue. The main cause of ...