Back on December 22, 2020, I detailed why Peloton Interactive (PTON), with a market capitalization of $42.2 billion was ridiculously overpriced at $161 per share. I recommended selling your shares if you were an owner or shorting Peloton if you weren’t.

Today, Peloton closed at around $83 per share, with a market cap of $24.3 billion. So had you taken my advice and shorted 100 shares, you’d be sitting with a $7,800 profit representing a whopping 145% annualized return.

While some of Peloton’s price decline is attributable to recent issues with defective equipment requiring a product recall, the decline in price began much earlier, as savvy investors began selling their positions to less sophisticated investors who were jumping on the Peloton bandwagon.

# SELL!!!

Peloton Interactive (PTON), the innovative company that pioneered gluing an iPad to the handlebars of a stationary bike, this week was added to the NASDAQ 100 stock index. Based on a market cap of $42.2 billion, Peloton became one of the 100 largest non-financial companies traded on NASDAQ.

With only a market cap of $5 billion prior to the pandemic, in the past nine months Peloton’s market cap has soared past much better-known companies, such as Marriott, Mitsubishi Electric, General Mills, Fiat-Chrysler, eBay and the Ford Motor Company.

With the size of the home fitness market currently at $11.5 billion and Peloton yet to generate a profit on $1.8 billion in revenue, one wonders about the company’s valuation. I always view things from the perspective of a buyer or seller. So, if a buyer purchased Peloton for $42.2 billion, what would their return look like? A simple, “back-of-the-envelope” analysis would look something like this:

If the buyer instead bought 10-year Treasury bonds, they’d get a 0.9% return. Pretty poor, but very safe. If the buyer bought a high-yield junk bond fund, the return is about 4.5% and high-dividend ETF returns are in the 5% to 8% range. Thus, an investor writing a $42.2 billion dollar check to buy Peloton, a high-flying company who’s growth has been driven by a “once every century” pandemic, would want a return in excess of 10% as compensation for assuming such huge risk.

# Installing Kali Linux in Parallels Desktop – Part 3

In Part 1 of this post, we downloaded the most recent Kali Linux ISO and verified its checksum. In Part 2, we installed Kali Linux in our virtual machine and logged ourselves in. We’ll now update and upgrade our Kali Linux installation and install Parallel Tools.

**Step 1: Updating and Upgrading Kali Linux**

Start up Parallels Desktop and select the Kali virtual machine.

Once Kali Linux starts, log in using the “root” credentials set in Part 2. We’ll use the Linux Terminal to perform the next two steps. Start the Terminal by clicking its icon in the upper left as shown here:

Once the Terminal starts, type the following at the command line:

**apt-get update**

and press **Enter**.

Kali will process all of the published updates since the ISO distribution used for the installation.

# Installing Kali Linux in Parallels Desktop – Part 2

In Part 1 of this post, we downloaded the most recent Kali Linux ISO and verified its checksum. We’ll now use that ISO to install Kali in Parallels.

**Step 1: Installing the ISO**

Start Parallels Desktop and select **File => New** from the menu.

Click the center selection, which reads **Install Windows or another OS from a DVD or image file**, then click **Continue** in the lower right corner. You will be presented with the following screen:

As you can see, my system has already located the downloaded ISO. If your system didn’t locate the ISO, simply click **Choose Manually** and navigate to the ISO download location from Part 1 of this post. Once you’re ready to proceed, click **Continue** in the lower right.

The next screen will ask you for the name of the virtual machine. You can choose anything that makes sense to you. I chose “Kali Linux”. You can also change the location of where the virtual machine will be saved. The default will be the “Parallels” folder, which is fine. It can always be moved later. Next, click **Create** in the lower right and the installation process will begin.

# Installing Kali Linux in Parallels Desktop – Part 1

Installing Kali Linux in Parallels Desktop is a straight-forward process. Trouble ensues when important installation steps are either skipped or performed in the wrong order. This post is Part 1 of a step-by-step guide on getting Kali up and running on your virtual machine of choice, Parallels Desktop.

**Step 1: Obtain the latest Kali ISO**

The latest Kali image file (ISO) can be found here: https://www.kali.org/downloads/

I selected the “Kali Linux 64-bit” image, but your selection may vary depending on the specifications of your machine. The download page gives you two download options (*see image below*): (1) you can click on the image name link to download the ISO directly or (2) you can click on the “Torrent” link to download the torrent file for the ISO. You will then need a torrent client to open the torrent file and begin the download.

# Matrix Multiplication Using Excel

Using Excel’s formula for matrix multiplication (MMULT) is not as straight-forward as using the other built-in formulas provided by Excel. By simply following the MMULT formula wizard, you will get a head-scratching result if you are not aware of the two additional steps necessary in using this formula (or any Excel formula that uses an array as input, such as TRANSPOSE).

Before beginning, we’ll do a quick review of matrices. A **matrix** is an m x n array of real or complex numbers, where *m* is the number of rows and *n* is the number of columns. The matrix is *square* if m = n and *rectangular* otherwise. A **vector** is a matrix of one row or column: a m x 1 matrix is a column vector and a 1 x n matrix is a row vector.^{1}

# Getting Started With PhoneGap

In this post, I’ll describe how to install both PhoneGap and the Ripple extension for Chrome and then fire up a “Hello, World” app. As mentioned in an earlier post, there are two versions of PhoneGap, PhoneGap Desktop (GUI) and PhoneGap CLI (command line). Here, I’ll be installing Desktop. First, it’s easier to use and second, from reading the documentation, I get the sense it’s where Adobe will be putting its future efforts.

# The Sieve of Eratosthenes

Yesterday, I reviewed The Music of the Primes: Searching to Solve the Greatest Mystery in Mathematics, a book by Marcus du Sautoy.

In the book, du Sautoy explains the Sieve of Eratosthenes, an algorithm for finding all the prime numbers under a given limit. The concept is surprisingly simple – for a set of numbers less than N, begin with the first prime number (2) and throw out all of its multiples (4, 6, 8, etc) up to N. Then start over with the next number remaining (3) and throw out all of its multiples up to N. Some multiples of 3, such as 6 and 12, will have been thrown out in the prior step. Keep repeating the process until there are no numbers less than N left to be thrown out.

# Book Review: The Music of the Primes

I just finished reading Marcus du Sautoy’s “The Music of the Primes: Searching To Solve the Greatest Mystery in Mathematics”. If a book about a subject as dense as the Riemann Hypothesis can be described as a page-turner, this is the one. Using analogies and metaphors, du Sautoy enables the reader to appreciate the difficulties, as well as the successes, mathematicians have experienced in trying to prove a conjecture that has defied proof for almost 200 years. The book’s audience is the lay reader and thus, does not delve too deeply into zeta functions, imaginary numbers and quantum chaos theory. In other words, after reading, you still won’t be equipped to find a proof of the Hypothesis and claim the $1 million Clay Millennium Prize.

# Evaluating Adobe PhoneGap

In evaluating multi-platform development tools for mobile, I came across PhoneGap, Adobe’s entry into the marketplace. What makes PhoneGap unique is that apps can be developed using standard web development technologies, such as HTML, CSS and javascript. What surprised me was the access PhoneGap provides to device-level features, such as the accelerometer, camera and GPS. I thought that level of access required Xcode, or at least a multi-platform tool like Xamarin, with its reliance on C# and Mono .NET. PhoneGap apps will even handle push notifications.