Posts on (x)slates
/posts/
Recent content in Posts on (x)slates
Hugo  gohugo.io
enus
© 2019 — (x)slates  All Rights Reserved.
Wed, 19 Jun 2019 06:54:10 +0200

Quadratic equations
/posts/quadraticequations/
Wed, 19 Jun 2019 06:54:10 +0200
/posts/quadraticequations/
An equation containing a seconddegree polynomial is called a quadratic equation and has the form
$$ax^2 + bx + c = 0$$
There are a handful of ways to handle these types of equations; you can solve them by factoring, use the square root property, or completing the square. However, the fastest method is to use the quadratic formula

Complex numbers
/posts/complexnumbers/
Tue, 18 Jun 2019 12:09:37 +0200
/posts/complexnumbers/
Complex numbers, $\mathbb{C}$, exist to fill a void in the real numbers set, $\mathbb R$. This void is the fact that we know how to take the square root of any positive real number, however, we need a way to define the square root of a negative real numbers. Because these square roots can’t—by definition—be real numbers, they’ve been historically called imaginary numbers.

Exponents
/posts/exponents/
Mon, 17 Jun 2019 15:35:15 +0200
/posts/exponents/
Exponents, in the simplest case, are a way to represent very large (or very little) numbers, which is most evident in the convention of scientific notation. Scientific notation refers to numbers written in the form $a \times 10^n$, where $1 \leq a < 10$, meaning that the value of $a$ is between one and ten.

Linear equations in one variable
/posts/linearequationsinonevariable/
Sun, 16 Jun 2019 12:20:27 +0200
/posts/linearequationsinonevariable/
A linear equation is an equation of a straight line and as the form
$$ax + b = 0$$
where $a$ and $b$ are real numbers, $a \neq 0$. You can categorize linear equations as identity equations which are true for all values of the variable, $3x = 2x + x$; conditional equations which are true for only some values of the variable, $5x + 2 = 3x  6$; and inconsistent equations which result in false statements, $5x  15 = 5x  20$.

Logarithms and roots
/posts/logarithmsandroots/
Sun, 16 Jun 2019 09:54:41 +0200
/posts/logarithmsandroots/
Given the expression $a^n = b$, logarithms answer the question “what’s the number of times $a$ needs to be multiplied by itself to get $b$?”, that’s what $\log_a b = n$ does. Roots answer the question “what number $a$ multiplied by itself $n$ times gives me $b$?”, that’s what $\sqrt[n]{b} = a$ does.

Let them churn
/posts/letthemchurn/
Sat, 15 Jun 2019 13:04:07 +0200
/posts/letthemchurn/
Businesses don’t want their customers to churn. Most companies treat churn as a onesided relationship where the customer should not have the right to move on from the product.
Technically, customers don’t churn (unless, say, they delete their subscription to a service); they just stop using your product. Depending on how much time has passed, the business might put the customer into a churned segment.

Linux porn, leaving social media, and minimalism
/posts/linuxpornleavingsocialmediaandminimalism/
Sat, 15 Jun 2019 10:41:31 +0200
/posts/linuxpornleavingsocialmediaandminimalism/
I decided to give a try to the Linux world the past couple of months. It’s been almost ten years since I used Ubuntu and I decided to use Linux Mint this time around.
As I was getting used to Linux all over again, I got to experience a new sphere of the Internet I didn’t know about and their quirks.

Reticulate
/posts/reticulate/
Fri, 14 Jun 2019 11:30:42 +0200
/posts/reticulate/
The reticulate package is a cool addition to the data analysis ecosystem. However, you’ll lose your mind trying to figure out how to set up virtual environments.
This site is built with Hugo. Although there’s an R package, blogdown, that streamlines the management of a Hugo blog for you, I didn’t want to manage my site via RStudio.

Polynomials
/posts/polynomials/
Thu, 13 Jun 2019 09:28:32 +0200
/posts/polynomials/
A polynomial is a sum or difference of terms, each consisting of a variable raised to a nonnegative integer power. In general, a polynomial is an expression of the form
$$a_n x^n + … + a_2 x^2 + a_1 x + a_0$$
Each real number $a$ is called a coefficient. The number $a_0$ that is not multiplied by a variable is called a constant.

Radicals
/posts/radicals/
Wed, 12 Jun 2019 09:34:24 +0200
/posts/radicals/
When the square root of a number is squared, the result is the original number. The reason why it’s called square root has to do with the area of the square that you obtain when graphing the radicand on the coordinate plane.
In general, the principal square root of a number $a$ is the nonnegative number that, when multiplied by itself, equals $a$.

Trading; a few rules of engagement
/posts/tradingafewrulesofengagement/
Tue, 11 Jun 2019 15:03:19 +0200
/posts/tradingafewrulesofengagement/
Over the past weeks, I’ve been listening to a podcast called Chat with Traders where you get to listen to professional traders share how they work.
Having no experience in the trading world, I thought it would be a good idea to try and pick up the topic by listening to conversations about it, rather than books.

Formulas, expressions, and equations
/posts/formulasexpressionsandequations/
Tue, 11 Jun 2019 09:08:00 +0200
/posts/formulasexpressionsandequations/
An expression is a group of mathematical symbols representing a number or a quantity.
$3a$
$2x + 8$
$a^2  89$
An equation is a mathematical statement indicating that two expressions are equal. The equation is not inherently true or false, it’s only a proposition; it’s truth value has to be calculated.

Real number classification
/posts/realnumberclassification/
Mon, 10 Jun 2019 14:40:49 +0200
/posts/realnumberclassification/
In Real Analysis you study real numbers and their properties.
The classification of real numbers (using set notation) goes like this:
natural numbers are the set of numbers we use for counting, $\mathbb{N}$ whole numbers are the set of numbers we count with plus the number zero, $\mathbb{Z^+}$ integers are the set of natural numbers, their opposites, and zero, $\mathbb{Z}$ rational numbers are the set of numbers that are ratios of integers, $\mathbb{Q}$ as a caveat, the denominator should be $\neq 0$ they can be represented as decimal numbers as well (terminating or repeating) irrational numbers are the set of numbers that can’t be represented as a fraction, $\mathbb{I}$ There are also a few others but they belong to more advanced treatments of number theory.

Right triangle trigonometry
/posts/righttriangletrigonometry/
Fri, 07 Jun 2019 13:46:05 +0200
/posts/righttriangletrigonometry/
In elementary geometry you learn a handful of definitions for the different types of angles that you study. Acute angles are between 0° and 90°, right angles are equal to 90°, obtuse angles are between 90° and 180°, and straight angles are equal to 180°.
Fig 1. Different types of angles

Growth fallacy
/posts/growthfallacy/
Thu, 06 Jun 2019 13:19:03 +0200
/posts/growthfallacy/
“When you’re a retailer, nobody tells you that your chain’s highgrowth days are over and it’s time to switch to a maturity strategy. To detect when you should begin transitioning from high growth to slow growth, you need to track the right metrics.” Stop Chasing the Wrong Kind of Growth  Harvard Business Review

Asking better business questions
/posts/askingbetterbusinessquestions/
Sat, 01 Jun 2019 12:58:05 +0200
/posts/askingbetterbusinessquestions/
In business analytics, it’s not unusual to get questions like:
“We launched a campaign last week, and we’d like to know how it performed.”
A request like this can end in a handful of ways:
(A) You’re lucky, and you manage to figure out a meaningful answer that the requester accepts.

Teaching yourself mathematics (now that you care)
/posts/teachingyourselfmathematicsnowthatyoucare/
Sun, 26 May 2019 12:44:00 +0200
/posts/teachingyourselfmathematicsnowthatyoucare/
Ironically, mathematics is one of the most hated school subjects while also being the most useful and applicable. I think many people realize the usefulness of mathematics once they grow up; which means that the topic’s relevance is poorly anchored in reality when we study it as kids. My interest in mathematics sparked late, when I was already a grown man with a fulltime job.

Eponymous Laws
/posts/eponymouslaws/
Fri, 24 May 2019 13:40:35 +0200
/posts/eponymouslaws/
For some reason, I really love eponymous laws, here’s a list of some of my favorites:
The Asimov corollary to Parkinson’s law: In ten hours a day you have time to fall twice as far behind your commitments as in five hours a day. Benford’s law of controversy: Passion is inversely proportional to the amount of real information available.

Compound blindness
/posts/compoundblindness/
Fri, 17 May 2019 18:50:27 +0200
/posts/compoundblindness/
The way companies measure growth can sometimes be ambiguous. Considering growing numbers in isolation is dangerous.
Suppose we have a record of increasing revenue over time.
Although I couldn’t find the technical term for it, I remember reading the term compound blindness to describe the situation in which an “impressive” growth rate does not take into account inflation, population growth or other forms of cooccurring natural compound growth.

Multiplication is scaling
/posts/multiplicationisscaling/
Wed, 15 May 2019 01:39:24 +0200
/posts/multiplicationisscaling/
We’re often introduced to multiplication as repeated addition. However, this is an incorrect model that leads to confusion when you start tackling more advanced mathematical topics. A better mental model is to think of multiplication as scaling. In simple words, when you multiply, you’re stretching a quantity $x$ by a factor $k$—even when you’re using fractions.

Interview with Erik Bernhardsson
/posts/interviewwitherikbernhardsson/
Fri, 10 May 2019 00:39:37 +0200
/posts/interviewwitherikbernhardsson/
I found out about Erik Bernhardsson’s Twitter profile by chance a few years back and was immediately fascinated by his experience and achievements. His website is one of the few that I read on a regular basis.
I contacted Erik because I wanted to know more about who he is and his story.

Goodhart's Law
/posts/goodhartslaw/
Sun, 05 May 2019 00:25:30 +0200
/posts/goodhartslaw/
Goodhart’s Law states that: “When a measure becomes a target, it ceases to be a good measure.”
The first comment in this Lesswrong’s article about the law is indicative of this phenomenon in industry:
A good example from my history of doing this is when I worked for an ISP and persuaded them to eliminate “cases closed” as a performance measurement for customer service and tech support people because it was causing emailbased cases to be closed without any actual investigation.

Competitive advantage
/posts/competitiveadvantage/
Thu, 25 Apr 2019 00:32:45 +0200
/posts/competitiveadvantage/
I stumbled upon an interesting article from Harvard Business Review that explores how companies build competitive advantage from a behavioral point of view.
A few illuminating excerpts.
(…) the idea that purchase decisions arise from conscious choice flies in the face of much research in behavioral psychology. The brain, it turns out, is not so much an analytical machine as a gapfilling machine: It takes noisy, incomplete information from the world and quickly fills in the missing pieces on the basis of past experience.

Job hopping across industries
/posts/jobhoppingacrossindustries/
Sun, 10 Mar 2019 00:35:31 +0200
/posts/jobhoppingacrossindustries/
I used to believe that job hopping was not a good career strategy for a few reasons:
You need time to make a dent in an organization. If you hop often you rob yourself of a chance to make an impact. Climbing through the ranks where people already know you might be more comfortable than doing it in a new environment.

Some thoughts on work
/posts/somethoughtsonwork/
Thu, 14 Feb 2019 23:11:52 +0200
/posts/somethoughtsonwork/
Here are some thoughts on my experience working in the tech industry You can’t manufacture team culture. It’s the result of organic habits and behaviors that a group of people develops over time, which is also the reason why workshops and topdown change initiatives meet so much resistance.
Don’t have a meeting if you don’t have an agenda.