# Calculus I, II, II, and differential equations College Park Tutors Blog

## Optimization: using calculus to find maximum area or volume

Calculus 1, Math120
Feb 18, 2018

Optimization, or finding the maximums or minimums of a function, is one of the first applications of the derivative you'll learn in college calculus.

In this video, we'll go over an example where we find the dimensions of a corral (animal pen) that maximizes its area, subject to a constraint on its perimeter. Other types of optimization problems that commonly come up in calculus are:

• Maximizing the volume of a box or other container
• Minimizing the cost or surface area of a container
• Minimizing the distance between a point and a curve
• Minimizing production time
• Maximizing revenue or profit

This video goes through the essential steps of identifying constrained optimization problems, setting up the equations, and using calculus to solve for the optimum points.

## Review problem - maximizing the volume of a fish tank

You're in charge of designing a custom fish tank. The tank needs to have a square bottom and an open top. You want to maximize the volume of the tank, but you...

## An Overview of the Natural Logarithm: Common Questions and Mistakes Explained

Calculus 1, Math140
May 18, 2017

## What is the natural logarithm?

This part is optional, as students are unlikely to be tested on this material, but if you would like a better understanding of what the natural logarithm means conceptually, you may want to read this section.

Sometimes students will see $ln(x)$ on a paper, refer to it as "el-en", but not know what it actually means. Perhaps the easiest way to understand it is to know its relation to the number, $e$. Remember: $e$ is just a constant, approximately equal to $2.71828$. $e^x$ and $ln(x)$ are inverses.

What does this mean? Think about cubing a number and taking the cube root of a number. Imagine that we start out with the number $7$. If we cube it, we get $343$. If we take the cube root of this new number, $343$, we get $7$, which is the number we started with. Similarly, imagine that we start out with the number $125$. If we take the cube root, we get $5$. If we cube this new number, $5$, we get $125$, which is the number we started with...

## Using calculus to minimize inventory costs for a manufacturing operation

Calculus 1, Math120
Mar 10, 2016

A lot of the "word problems" that come up in calculus seem silly and contrived, because they are. The inventory cost problem, however, is something that comes up in real-life manufacturing scenarios all the time - how can I minimize my operating costs? In fact, the problem we see here today is a simplified version of a problem I covered in a DETC conference paper that I published a few years back.

Hot Bod Jacuzzi & Spa Company is launching a new hot tub - the Neverleak Massage-o-matic DeLux. They have an exclusive deal with Gallmart to supply the retail giant with 10,000 units over the next several years. The hot tub shells are made using injection-molding, in which molten plastic is squirted into metal molds at high pressure, and then allowed to cool. Once the shell has cooled, assembly workers finish the product by attaching the hoses and motors and installing insulation.

Being a small company, Hot Bod doesn't have their own factory - they will have to rent space from the Berry Plastics Corporation. Berry Plastics char...

## Gotta love xkcd...

Calculus 2, Math141
Apr 19, 2015

Thanks xkcd. You're always there to pick up the slack.

## A flowchart for dealing with mathematical series

Calculus 2, Math141
Apr 19, 2015

The chapter on series is notorious for making calculus students want to hurl their textbooks into a fire, curl up into a fetal position, and sob uncontrollably the night before the exam (I've been there myself).

Honestly, its not that series are so difficult as much as it requires you to remember a lot of rules, how to apply them, and most importantly, in what order to apply them. And most calculus courses just don't do all that great a job of explaining this - they just hurl a bunch of theorems at you, a few tests, and tell you to sort it all out yourself. To help with this, I've created a flowchart that explains how to approach solving a mathematical series. The important things to keep in mind are:

• There is a BIG difference between finite and infinite series. Look at the problem carefully before you decide how to approach it.
• Many tests are inconclusive about whether an infinite series converges/diverges. In that case, you must try another test.
• Just because we can prove that an infinite series converges, doesn't mea...