Atok's Math Blog

My name is Janus, and I am a 25-year-old math-econ student at Aalborg University, Denmark

[just-shower-thoughts]

The stereotypical complicated math equations scrawled on chalkboards in scifi movies must seem straightforward or BS to actual physics and math students.

[mamoru]

[bitsow]

4800 players, Beethoven’s 9th Symphony Speedrun

[kaijuno]

its not even music anymore it’s just a shockwave that kills you instantly

[mathematok]

Funny how removing the context makes some things look silly 🤔

[jungle-ion]

Dude it’s still silly, the situations aren’t comparable. More orchestra players doesn’t make people play the song faster.

[mathematok]

[mamoru]

[bitsow]

4800 players, Beethoven’s 9th Symphony Speedrun

[kaijuno]

its not even music anymore it’s just a shockwave that kills you instantly

[mathematok]

Funny how removing the context makes some things look silly 🤔

[mathematicalmemer]

[mathematok]

Quick tip: x% of y = y% of x

For example, with x = 20 and y = 50:

20% of 50 is 10

50% of 20 is also 10

This holds true for any two real numbers x and y, and you can easily see why by simply looking at the definition of percentage:

[mathematok]

I’m bringing this blog back from the dead

It’s been like... 8 months since I last posted on this blog, whops.

Here’s what I’ve been up to since then:

Got my Bachelor’s degree in Mathematics-Economics!

Got a student job at a big energy trading company!

Started on my Master’s degree in Mathematics-Economics, specializing in Financial Engineering!

Passed all exams of the first semester!

Considering doing a PhD!

Moving in with my girlfriend in two months!

Feeling good!

I’d like to actually keep this blog more active from now on, as well as provide interesting posts (now and then), so I’m considering changing it up slightly by posting :

Updates from my semester project; I’ve been wanting to try making a summarized (perhaps interactive?), more accessible version of a project, to practice communicating math and data science

Updates from my courses; this semester I’m taking Data Mining, Quantitative Finance, and Bayesian Inference and Mixed Models ― maybe if we learn something particularly interesting, I could post about it

Stuff related to R (the programming language)

Ideas?

I don’t think I’ll have very much time for providing math help, so don’t expect immediate answers if you inbox me (you’re still very much welcome to ask questions anyway, of course).

But yeah, I’ll try to make more of an effort to post regularly.

[mathematok]

I’m on the 6th and final semester of my Bachelor’s degree, and this has been the most draining semester so far, god damn

I’m currently halfway through my exams; nailed both Time Series Analysis and Financial Engineering, but next up is Spatial Statistics, and I’ve not been this nervous about an exam since Analysis I...

It’s on Monday, wish me luck lol

[rangi42]

Theorem 7.2. It is NP-complete to decide whether a given target location is reachable from a given start location in generalized Pokémon in which the only overworld game elements are enemy Trainers.

“Classic Nintendo Games are (NP-)Hard“ [PDF]

Including such diagrams as Figure 23: XOR-Crossover gadget for Pokémon

(via rangi42)

[mathematok]

If you formalize those “GENIUS ONLY” posts, they kinda sound like textbook exercises from an intro course or something

[badsciencejokes]

Why did the chicken cross the road?

The intermediate value theorem.

[mathematok]

Survived four hours in Purgatory (i.e. Partial Differential Equations exam) today

[suigintou]

wait is 5! = 120 an actual math thing i just reblogged it bc i sincerely believe that yelling a number makes it bigger 

[bunyipandler]

An exclamation point after a number means factorial. Five factorial is 5 times 4 times 3 times 2 times 1. Three factorial is 3 times 2 times 1, etc.

[maeamian]

But the more exclamation points after a number, the less big it is, a double factorial is every other number, so 6!! is 6 times 4 times 2, which is less than 6!, So yelling a number makes it bigger, but yelling louder makes it smaller again

[dragongirltitties]

it’s because you scared it

[mindfuckmath-deactivated2016062]

[mathematok]

A long overdue updated icon for this blog

[mathematok]

Multiplying large numbers in your head — explained

If you’ve seen this image:

(likely with comments such as “why didn’t we learn this in school!?”), perhaps you’ve wondered which numbers this would work for, and why. 

It turns out to be a result of simple algebra that works for any two numbers, as long as you’re interpreting the method correctly.

The image explains very little, but algebraically here is what’s happening:

So with the numbers used in the image, it looks like

Basically, by expressing two numbers as a difference from 100, their product can be calculated in a way that’s easy to do in your head. Be careful though; from the image, one might thing you’re just concatenating the red and the blue parts of the number, but you’re actually adding them together.

As I said above, it works for any a and b. For example, we could choose a = 105 and b = 5 and get

That said, since the purpose is to make it easier to calculate, it’s limited which values this method is actually practical for.

Hence why they didn’t teach it in school :^)

[mathematok]

Why would you integrate a line integral with respect to a variable -- say, x or y -- instead of arc length? My book just kind of threw it out there and didn't explain where it came from. Maybe what I'm asking is what the geometric interpretation of it is? I don't know. (integrating f(x,y) dx vs integrating f(x(t),y(t)) dt along some curve)

Hmm, I’m not really sure, but it could sound like you’re evaluating something else than the line integral, since you’re fixing y and integrating only wrt x.

If this is for a course you’re following, I’d say ask the lecturer about it :/

[twitterscreencaps]

[hypoel]

the speed limit is 720 fuCKING MILES PER HOUR.

[dexciti]

It’s actually 45… how… how did you get 720?

[thebatterypower]

No? Shouldn’t it be 180?

[scurvy-dogs-deactivated20191030]

No, I think 45 is right. 2 times 45 is 90, and 360 divided by 4 is 90, so yeah, 90=90.

[thebatterypower]

Yeah, but if x = the sum of 360/4. then it should be 2 multiplied by x, (90). Yeah? If it was 2 times 45, 360/4 would have to equal 45, and it doesn’t.

[wtfisthinprivilege-deactivated2]

I dont get what yall are saying

But 2x = (360÷4) is 2x=90 so x = 45

[official-mugi]

Tumblr: School is dumb I don’t need math Tumblr: The speed limit is 720 mph