Difference between ‘violet’ and ‘purple’
People say that a picture is worth a thousand words, so let’s take a look at the two colours in comparison (there are various shades of (...)

What does it mean for a function to be welldefined?
A common addendum to a formula defining a function in mathematical texts is, “it remains to be shown that the function is well defined.” (...)
March 3, 2015 – Jakub Marian – Mathematics

Map of life expectancy in Europe
Life expectancy at birth is defined as the number of years a newly born individual in the given country is expected to live on average, (...)
February 25, 2015 – Jakub Marian – Maps

Comparison of the largest star (UY Scuti), the Solar System, Sun, Jupiter, and Earth
Some objects in the Universe are huge, but it is hard to imagine how huge they really are. To help my readers with that, I made the (...)
December 26, 2014 – Jakub Marian – Physics

Is 0.999… (repeating) equal to 1?
The short answer is yes. $0.\bar 9$ (zero point 9 repeating) is exactly 1. However, a lot of people find this result counterintuitive (...)
October 16, 2014 – Jakub Marian – Mathematics

By the way, have you already seen my brand new web app for nonnative speakers of English? It's based on reading texts and learning by having all meanings, pronunciations, grammar forms etc. easily accessible. It looks like this:
Do certain numbers in a lottery have a higher probability of winning than others?
Does going for “nice” sequences of numbers, like 1 2 3 4 5 6, reduce the probability of winning in a lottery? Some people think so. “Have (...)
September 25, 2014 – Jakub Marian – Mathematics

Will computers ever be smarter than humans?
When I was a child, I was fascinated by the idea that some day we will be able to construct computers that will be smarter than us. Later, (...)
September 12, 2014 – Jakub Marian – Mathematics

Average IQ in Europe by country (map)
When we speak about IQ, it is important to understand that the common idea that IQ measures your “innate” or “genetic” intelligence is a (...)

Arithmetics in which you can divide by zero
When I was still in primary school, I was fascinated by things you “can’t do” in mathematics and developed a “theory” of division by zero. (...)
June 8, 2014 – Jakub Marian – Mathematics

Is it possible to divide by zero?
This is a common question on mathematical discussion boards, with people sometimes feeling that mathematicians are too closedminded for (...)
June 7, 2014 – Jakub Marian – Mathematics
