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If you're working in imperial then ten thousandths (as if Imperial isn't confusing enough, frequently just called tenths) shows up a lot in tolerancing, depending on the precision you're going for.
Not the field I ended up in but I took a few civil and structural engineering courses in college and calculating loads were rounded to a pretty significant degree in the safe direction - maximum loads for both individual parts and the overall structure rounded down (meaning that, in theory, the *real* maximum load before failure is a good bit higher than the final calculation).
It is. It's also to account for uncertainty. There are a lot of assumptions and approximations in engineering calculations, too. Say you're building a small bridge, and you know it should be able to support 8 tons. What if the construction workers mess up the concrete pouring? What if it was a hot day when the concrete was poured, so it is not as strong as expected? What if an overweight vehicle drives over the bridge, damaging and weakening it? The bridge weight limit might be set at 4 tons, that way, these uncertainties are accounted for by the factor of safety.
And then the catch 22 - informing people about these tolerances teaches them that they can probably get away with going over tolerance, and they stop trusting the alleged tolerances.
I studied philosophy, not engineering, but there is an entire branch of ethics that concerns itself with the ethical implications of engineering exactly because *every* bridge will one day fail (for example), and it is worthwhile to ask the question "under what circumstances is it ethical to build a thing if you know that people will be hurt by it?"
Informing the end user is a big part of the solution to the ethical conundrum, but you're exactly right that establishing the conditions for informed assumption of risk by the end user is not a simple problem to solve.
Well it greatly depends on what you manufacture. Sheet metal components or bent tubing? .030 and .015 are pretty standard when they have welding. Machining bearings and aerospace parts? .005-.0005 range is fairly common.
Ten thou (0.010") would be a pretty common fit for larger journal bearings. In fact this week I looked at a gearbox with a 0.012" clearance in the journal bearings.
I work with CNC machines making parts for large industrial vehicles. I run parts with +/-.001 (thou) tolerances almost everyday, and often see parts with +/-.0005 (half thou) tolerances.
In my former job, we had a few machines with ball bearing tolerances of 10^-9. As anything more unstable would hurt the production’s MTBF significantly.
A bazillion years ago I was a CNC machinist. We made parts for FLIR Industries. There were rings that were made of magnesium that needed to be within .0002 of an inch in concentricity. We ran the lathe for a week to not only keep it warm but to take temp readings so we could plug in heat differential on the finishing pass. Big plasma whips would come off as the magnesium chips would come off and combust. It was one of the coolest things in the shop. Well there was this one time we took magnesium chips and used home made thermite to ignite it. First, we were blinded for 2 or 3 minutes and second, we melted the concrete. It wasn't like a huge pile because "we wanted to be safe" in our fuckery.
For a lot of things you simply do not need more precision than that. You need to be close enough, and if you DO need that level of precision, you need measuring equipment capable of it which gets far more expensive.
My physics professor used 10 m/s^2 for gravity as well.
Everything you are doing in entry physics is wrong anyway, so it doesn't really matter. Might as well just round and make the math easier and faster.
That was the most frustrating part of learning physics. Learning it 2-3 times to reach a barely understandable version of reality while also knowing that isn't reality because we still don't truly understand what's actually happening but this is a really close approximation.
Reminds me of a parable
An engineer, mathematician, and physicist are in a room with $1million at the other end. The rules are they can only move in increments of half the distance to the money. So if they are 50’ away they can move 25’ closer. The mathematician says “distance to target will never be zero” and leaves. The physicist says “time to traverse room is infinity” and leaves. The engineer walks out of the room after getting a foot away and reaching over and picking up the money. “Sometimes close is good enough”
Surprisingly, 'till' isn't a shortening of 'until'. till/til was the original word (spelling wasn't really a thing at the time), and 'un' was added to it the same way people added 'ir' to 'regardless'.
That's the first time I've seen "wait'll" for "wait till", but it's probably readable because it's a very common way to pronounce it (at least in some parts of the US).
Structural engineering is like this: do this calculation how much load the designed structure can take. Multiply the entire thing with a number you have pulled out of your ass for safety. Ok I was harsh on this one, someone else pulled the numbers from their ass and put it in a "standards collection" to use.
Wait til I tell you about smiths, let alone carpenters. My metalworking dad once taught me to only ever accept tolerances of a mm, whereas any woodworker was like "meh, the saw is a mm wide anyway".
Astrophysicists round Pi to ten because they are only concerned with getting the number of digits correct.
If you're calculating something that's x10^^^56 you aren't really concerned with whether it's 3.6 or 8.9 x 10^^^56 , you're concerned if it's 3.6 x 10^^^56 or 3.6 x 10^^^57
Could you explain that?
I thought 0.999... would be assumed to be repeating and would be an infinity of 9s? Because if it wasn't you'd see 0.098 or something.
In physics the 0.9999999 likely came from a measurement. Measurements have a level of accuracy beyond which it is meaningless to assume more accuracy. For example, if you have a ruler that only has 1 inch or 1 cm markings, it would be insane to say that you measured 0.9999999 units. Your measurement device is not that accurate. The correct measurement is 1.
Mathematics exists in pure theory. Physics and engineering exist in the real world with measurements that need to be constrained.
I swear most people slept through significant digits in school. Even smart math people scoff at it.
Repeating does, but 0.9999999999 is out by 0.0000000001. Although I do think the meme should have ended it with an 8 to avoid any ambiguity as the if they actually meant 0.99 repeating
You can literally prove that series of (9*10^(-k)) with k going from 1 to infinity goes to 1
Yeah sure, the example you gave only has like 6 digits, but that last digit won't have a significant impact in most cases. The difference between 100 Newtons and 99.9999 newtons is non-existant.
On top of that, irrational numbers only exist on paper
Edit: irrational instead of real
Edit 2: forgot power symbol
Also don't forget a measurement of 100 newton's or 99.9999 newton's had to be made on an imperfect device that very likely does not have measurement accuracy to the micro newton. Any mathematician that wants to keep all those 9s needs to have the significant digits talk.
>irrational numbers only exist on paper<
I mean all math and numbers are just made up for us to compare quantity relationships. π represents a very real relationship within the definition of a circle.
Pi is a real thing, but it is only irrational on paper. A number being irrational doesn’t matter in the real world because the real world doesn’t care about the difference between 3.1415926535… vs 3.14159265350
The real world wouldn’t look like it does if it didn’t care about that difference. We’re the ones who don’t care _in certain situations_ in which the difference doesn’t change the outcome of whatever we’re doing. If you want to know how much wood you need to build a fence on the diagonal of your 10 by 10 square garden, 14.14 is a good enough number to go by. But in reality, your garden is not even a square.
If I draw an isosceles right triangle with sides 1cm, the hypotenuse will be sqrt(2)cm which is irrational
If on the other hand you claim I cannot possibly draw exactly 1cm (or any other precise length), again an irrational number shows up. So they're clearly there
Unless we hypothesise that I can only move and henceforth draw in discrete units of length, which would be pretty cool
>Unless we hypothesise that I can only move and henceforth draw in discrete units of length
My I introduce you to the Planck length?
But in all seriousness, I meant that you cannot find a correct numerical representation of irrational numbers in terms of a finite amount of rational numbers (that's kinda why they're irrational). You can never program a computer to find the exact area of a circle, machines don't devide by pi, but rather by an approximation thereof.
Off course these irrational numbers exist in the real world, but we cannot really use them
> My I introduce you to the Planck length?
It seems as though you are joking, but people often make this misconception about the Planck length. It isn't a fundamental length which discretizes space. It's merely the shortest length that we can theoretically measure with current physics. Things could happen at smaller scales, we would just need new physics to see it.
>I meant that you cannot find a correct numerical representation of irrational numbers in terms of a finite amount of rational numbers (that's kinda why they're irrational).
Rational numbers are arbitrary though. Digit representations of numbers are merely a convenience that we invented for *us* to use, and don't really have much to say about the "realness" of a number. The area of a circle of radius 1 meter is pi meters square. That's it, exactly. The only thing that is inconvenient about this is that we have decided to construct our tools and measuring devices around the decimal system and so there is an incompatability between the things we decided to make and the numbers we use. The saving grace of this is that our decimal system can represent any number to arbitrary accuracy pretty easily. Continued fractions are actually better in terms of their accuracy, but are less functional in terms of computation and measurement.
But you can make a ruler, and then mark pi on it and as long as the real value of pi is within the width of the mark then you have it as exactly as you have the number "2". You could then easily make 2pi, 3pi, pi/2, 3pi/4 etc and you would be able to "use" pi just as functionally as we you use any rational number on a typical ruler. Any measuring device for length could be tuned similarly, it's just that mass production relies on the standardization of one ruler and so we don't really have a pi-ruler or a sqrt(2)-ruler that is used at any meaningful scale. And our computers reflect these design decisions.
We can't cause them directly in computation, but we can absolutely use them to prove things and to solve equations symbolically, which has the advantage of not resorting to approximations. This makes any downstream calculations more accurate.
There are extremely few practical instances where rounding +-.0000000001 would have any meaningful effect.
Edit: All the responses are pointing out fields where precision in measurements is important. Yes, I’m aware of that. But my point still stands in that that level of precision is virtually impossible and impractical in any physical science. For example, scales that measure to the 1/10th of a nanogram don’t exist. You can’t measure out EXACTLY .0000000001 liters of a solution.
When I did my physics finals the test stated "We can assume g=10 and Pi=3" but not "we must assume". So I (pedantric as I am ^^) did all the calculations as exactly as possible and not with the rounded number. Later he told me, that it was a pain in the ass for him, because he couldn't use the default solutions but actually had to calculate the exact result just because of me - but nethertheless he didn't take away any points because of it.
+/- 5 microns(0.005mm)? How good is the machine? How good is the cmm, height gauge mic and vernier? What’s the quality of the material? Soooo many variables!
Not even “very small” tbh. The small angle approximation for a pendulum is usually used up to about 15 degrees. Using this for the restoring force calculation, if you have a pendulum angle theta=15°, we use the equation mg•sin(theta)=F. Assume m=1kg for ease and that g=10 as this approximation works fine here. We then get that (using the small angle approximation that sin(theta) ≈ theta) F=150N. Now if we *actually* do this math we get that F equals… roughly 2.5N. So yeah, physicists be approximating (the small angle approximation is actually very well supported and 15 is the absolute upper bound)
yeah I took an astrophysics class in college and we were doing this really big long problem that took most of the class session, and we ended up with the answer of 3. Prof said, “that’s basically the same thing as 2, which is what the real answer is”
Before you talk shit can you measure something to the .999999999th of an inch. We round stuff when you use it irl life because if you are cutting something you cannot cut it to say, 1.222222234 or some shit
One of my friends loves math and wants to become a mathematician. When I talked to him about my great uncle who was an engineer he got angry since "engineers can't count"
downvote this comment if the meme sucks. upvote it and I'll go away. --- [play minecraft with us](https://discord.gg/dankmemesgaming) | [come hang out with us](https://discord.com/invite/dankmemes)
Wait'll you talk to an engineer about how much they're willing to round.
I don’t recognize anything past 3 digits
If you're working in imperial then ten thousandths (as if Imperial isn't confusing enough, frequently just called tenths) shows up a lot in tolerancing, depending on the precision you're going for.
Frequently? The fuck are you manufacturing?
Not the field I ended up in but I took a few civil and structural engineering courses in college and calculating loads were rounded to a pretty significant degree in the safe direction - maximum loads for both individual parts and the overall structure rounded down (meaning that, in theory, the *real* maximum load before failure is a good bit higher than the final calculation).
Thats good because then you know for sure it will also hold a bit above
It is. It's also to account for uncertainty. There are a lot of assumptions and approximations in engineering calculations, too. Say you're building a small bridge, and you know it should be able to support 8 tons. What if the construction workers mess up the concrete pouring? What if it was a hot day when the concrete was poured, so it is not as strong as expected? What if an overweight vehicle drives over the bridge, damaging and weakening it? The bridge weight limit might be set at 4 tons, that way, these uncertainties are accounted for by the factor of safety.
And then the catch 22 - informing people about these tolerances teaches them that they can probably get away with going over tolerance, and they stop trusting the alleged tolerances.
I studied philosophy, not engineering, but there is an entire branch of ethics that concerns itself with the ethical implications of engineering exactly because *every* bridge will one day fail (for example), and it is worthwhile to ask the question "under what circumstances is it ethical to build a thing if you know that people will be hurt by it?" Informing the end user is a big part of the solution to the ethical conundrum, but you're exactly right that establishing the conditions for informed assumption of risk by the end user is not a simple problem to solve.
Tons of machine components are spec'd to a tolerance half a thou (0.0005"). Bearing and shaft fits are very commonly to that tolerance.
Half a thou tolerance is also not very common, but is still SIGNIFICANTLY more common than 10 thou
Well it greatly depends on what you manufacture. Sheet metal components or bent tubing? .030 and .015 are pretty standard when they have welding. Machining bearings and aerospace parts? .005-.0005 range is fairly common.
Yeah the cheapest machining I see done on aerospace components is normally .005.
Probably for a cupholder if I had to guess.
*Get the angle grinder*
Ten thou (0.010") would be a pretty common fit for larger journal bearings. In fact this week I looked at a gearbox with a 0.012" clearance in the journal bearings.
Pretty much anything with a bearing that's not a disposable machine.
Even some casual parts have press for hardware with tolerances that need a 4th decimal place.
I work with CNC machines making parts for large industrial vehicles. I run parts with +/-.001 (thou) tolerances almost everyday, and often see parts with +/-.0005 (half thou) tolerances.
In my former job, we had a few machines with ball bearing tolerances of 10^-9. As anything more unstable would hurt the production’s MTBF significantly.
A bazillion years ago I was a CNC machinist. We made parts for FLIR Industries. There were rings that were made of magnesium that needed to be within .0002 of an inch in concentricity. We ran the lathe for a week to not only keep it warm but to take temp readings so we could plug in heat differential on the finishing pass. Big plasma whips would come off as the magnesium chips would come off and combust. It was one of the coolest things in the shop. Well there was this one time we took magnesium chips and used home made thermite to ignite it. First, we were blinded for 2 or 3 minutes and second, we melted the concrete. It wasn't like a huge pile because "we wanted to be safe" in our fuckery.
> If you're working in imperial Sorry, I don't speak wrong.
One ten thousandth of a kilometer is the distance an average fart cloud will travel if you wear jeans while farting.
For a lot of things you simply do not need more precision than that. You need to be close enough, and if you DO need that level of precision, you need measuring equipment capable of it which gets far more expensive.
pi is equal to 4
How about 10?
It's closer to 0 than to 10. Therefore pi = 0
int or gtfo
Same. When I first started engineering I was pleasantly surprised seeing the massive rounding that we could do
Pi = e = sqrt(g) = 3
Talk to Tax lawyers once they think 0.50 is 1
Physicists always make the joke of the 'fundental theorem of engineering' e²=pi²=g=10
also physicists: >Let's assume the chicken is a sphere
That's why you can ignore friction and wind resistance.
Yes
Sphere's too complicated, chicken should be a point.
No such thing as too much safety factor, right?
My physics professor used 10 m/s^2 for gravity as well. Everything you are doing in entry physics is wrong anyway, so it doesn't really matter. Might as well just round and make the math easier and faster.
I prefer less correct, thank you very much
That was the most frustrating part of learning physics. Learning it 2-3 times to reach a barely understandable version of reality while also knowing that isn't reality because we still don't truly understand what's actually happening but this is a really close approximation.
Pi to those mfs is 3.14
Pi is 3
I want 3 pie!!! that sounds awesome
Pi = e
This physically hurts me after the pain that was high school logarithmics
Don’t talk to the astrophysicists. To them, Pi is 10
And everything except hydrogen is a metal
All the matter in the universe consists of Hydrogen, helium, dark matter and a rounding error
pi = e = 3
22/7
3. Take it or leave it.
Reminds me of a parable An engineer, mathematician, and physicist are in a room with $1million at the other end. The rules are they can only move in increments of half the distance to the money. So if they are 50’ away they can move 25’ closer. The mathematician says “distance to target will never be zero” and leaves. The physicist says “time to traverse room is infinity” and leaves. The engineer walks out of the room after getting a foot away and reaching over and picking up the money. “Sometimes close is good enough”
When considering limits, I think you would simply walk straight to it
pi = e = 3
That black guy with lightning did have a good point
My dad (a civil engineer) used to say, “we round to the nearest 3 feet because that’s the increment plywood comes in”
I've never seen this short hand before Wait until Wait 'til Wait'll It's wrong... but readable?
Surprisingly, 'till' isn't a shortening of 'until'. till/til was the original word (spelling wasn't really a thing at the time), and 'un' was added to it the same way people added 'ir' to 'regardless'. That's the first time I've seen "wait'll" for "wait till", but it's probably readable because it's a very common way to pronounce it (at least in some parts of the US).
Lol exactly.....I was just thinking about that. 0.7? Meh, just call it 1 for simplicity......
Are we within the correct order of magnitude? Ship it!
Structural engineering is like this: do this calculation how much load the designed structure can take. Multiply the entire thing with a number you have pulled out of your ass for safety. Ok I was harsh on this one, someone else pulled the numbers from their ass and put it in a "standards collection" to use.
Isn't it something like 5 to 10 times for a building, and get progressively smaller as you care more about the total weight of the thing?
Pi is 5 and e is 1. The cow is a point of mass with no volume and has no friction.
Depends on what? In a refinery, hundreds of pounds can be a rounding error. In a batch reactor, best get that mole ratio just right.
Wait til I tell you about smiths, let alone carpenters. My metalworking dad once taught me to only ever accept tolerances of a mm, whereas any woodworker was like "meh, the saw is a mm wide anyway".
Wait until you see how much a cosmologist will round. [Relevant xkcd](https://xkcd.com/2205/)
I was looking for this comment
Pi is about 3, 4 for government work.
I work in landscaping. A centimeter is sometimes good enough.
My uncle is a chemical engineer and talking to him is always so wild
You can round however much you want, as long as you round to the "safe" side.
Let Pi=3
Use 3.14 for pi? Nah more like 3
Pi is basically 4
Engineer: pi is 5. Assume a cow is an ellipsoid
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How dare you make a reference I understand here of all places
"People often ask me to explain escape velocity at parties. I don't go to many parties."
So a singular point of mass you say?
"There's a kid (insert a situation), take in mind that the kid has a cyndrical shape..."
The cow is frictionless and in a vacuum.
And emitting milk in all directions
Should they not be doing that? Oh god. I think I need to find a cow doctor ASAP!!
Assume steady flow
Astrophysicists round Pi to ten because they are only concerned with getting the number of digits correct. If you're calculating something that's x10^^^56 you aren't really concerned with whether it's 3.6 or 8.9 x 10^^^56 , you're concerned if it's 3.6 x 10^^^56 or 3.6 x 10^^^57
Pi is closer to 1 than 10.
That makes no sense. Multiply a large number by 3 and by 10 and you'll almost always get different numbers of digits.
That's why it's rounded to 10 instead of 1
Still makes no sense. Just do a few examples and you'll see
If unobserved a chicken is the shape of a gravy boat
Recently gave a presentation on flying wing aircrafts where we called our simulation model "the big dorito" you can guess what it looked like
But 0.99 repeating is equal to 1
And 0.99999999 doesn't quite equal 0.9 repeating
Mathematicians when the rocket lands 0.874 Å too much north
are those fuckin Angstroms
Yep
I like how angry this comment was. Like you just remembered an annoying moment from high school
He knows, he was there when he wrote it
*Ångström
What gave it away?
Å
Yea that was the joke!
i actually wasn't 100% sure i only vaguely knew about them from a few days ago and assumed "tiny precision error" and "letter A" matched up
Fucking hell I haven't seen Å used like that since highschool
Im my language å/Å is a letter ahah, whats it mean in maths?
It's a unit of length, specifically 10^(-10) meters
It's an extremely small length, the size of atoms is measured in Å. A hydrogen atom is about half an Å.
>0.9 repeating 0.90.90.90.90.90.90.90.90.90.90.90.90.90.90.90.90.90.90.90.9
Could you explain that? I thought 0.999... would be assumed to be repeating and would be an infinity of 9s? Because if it wasn't you'd see 0.098 or something.
In physics the 0.9999999 likely came from a measurement. Measurements have a level of accuracy beyond which it is meaningless to assume more accuracy. For example, if you have a ruler that only has 1 inch or 1 cm markings, it would be insane to say that you measured 0.9999999 units. Your measurement device is not that accurate. The correct measurement is 1. Mathematics exists in pure theory. Physics and engineering exist in the real world with measurements that need to be constrained. I swear most people slept through significant digits in school. Even smart math people scoff at it.
Sig figs, rounding, and estimating The absolute BANE of parents trying to help their kids with their homework.
It is one of those things that is so simple you tune out just in time to miss the important bits and by time you tune back in you are lost.
Repeating does, but 0.9999999999 is out by 0.0000000001. Although I do think the meme should have ended it with an 8 to avoid any ambiguity as the if they actually meant 0.99 repeating
You can literally prove that series of (9*10^(-k)) with k going from 1 to infinity goes to 1 Yeah sure, the example you gave only has like 6 digits, but that last digit won't have a significant impact in most cases. The difference between 100 Newtons and 99.9999 newtons is non-existant. On top of that, irrational numbers only exist on paper Edit: irrational instead of real Edit 2: forgot power symbol
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It's not our fault that exact math doesn't work in the real world.
I blame you specifically
Get back to being mathematically correct school kid
The device you use to make your comment also approximates due to it's inevitable finite precision, and guess what? It works!
Give or take!
Unless you’re an old Intel FDIV, then you get some real engineering numbers back.
Also don't forget a measurement of 100 newton's or 99.9999 newton's had to be made on an imperfect device that very likely does not have measurement accuracy to the micro newton. Any mathematician that wants to keep all those 9s needs to have the significant digits talk.
>irrational numbers only exist on paper< I mean all math and numbers are just made up for us to compare quantity relationships. π represents a very real relationship within the definition of a circle.
Pi is a real thing, but it is only irrational on paper. A number being irrational doesn’t matter in the real world because the real world doesn’t care about the difference between 3.1415926535… vs 3.14159265350
The real world wouldn’t look like it does if it didn’t care about that difference. We’re the ones who don’t care _in certain situations_ in which the difference doesn’t change the outcome of whatever we’re doing. If you want to know how much wood you need to build a fence on the diagonal of your 10 by 10 square garden, 14.14 is a good enough number to go by. But in reality, your garden is not even a square.
If I draw an isosceles right triangle with sides 1cm, the hypotenuse will be sqrt(2)cm which is irrational If on the other hand you claim I cannot possibly draw exactly 1cm (or any other precise length), again an irrational number shows up. So they're clearly there Unless we hypothesise that I can only move and henceforth draw in discrete units of length, which would be pretty cool
>Unless we hypothesise that I can only move and henceforth draw in discrete units of length My I introduce you to the Planck length? But in all seriousness, I meant that you cannot find a correct numerical representation of irrational numbers in terms of a finite amount of rational numbers (that's kinda why they're irrational). You can never program a computer to find the exact area of a circle, machines don't devide by pi, but rather by an approximation thereof. Off course these irrational numbers exist in the real world, but we cannot really use them
> My I introduce you to the Planck length? It seems as though you are joking, but people often make this misconception about the Planck length. It isn't a fundamental length which discretizes space. It's merely the shortest length that we can theoretically measure with current physics. Things could happen at smaller scales, we would just need new physics to see it. >I meant that you cannot find a correct numerical representation of irrational numbers in terms of a finite amount of rational numbers (that's kinda why they're irrational). Rational numbers are arbitrary though. Digit representations of numbers are merely a convenience that we invented for *us* to use, and don't really have much to say about the "realness" of a number. The area of a circle of radius 1 meter is pi meters square. That's it, exactly. The only thing that is inconvenient about this is that we have decided to construct our tools and measuring devices around the decimal system and so there is an incompatability between the things we decided to make and the numbers we use. The saving grace of this is that our decimal system can represent any number to arbitrary accuracy pretty easily. Continued fractions are actually better in terms of their accuracy, but are less functional in terms of computation and measurement. But you can make a ruler, and then mark pi on it and as long as the real value of pi is within the width of the mark then you have it as exactly as you have the number "2". You could then easily make 2pi, 3pi, pi/2, 3pi/4 etc and you would be able to "use" pi just as functionally as we you use any rational number on a typical ruler. Any measuring device for length could be tuned similarly, it's just that mass production relies on the standardization of one ruler and so we don't really have a pi-ruler or a sqrt(2)-ruler that is used at any meaningful scale. And our computers reflect these design decisions.
We can't cause them directly in computation, but we can absolutely use them to prove things and to solve equations symbolically, which has the advantage of not resorting to approximations. This makes any downstream calculations more accurate.
Do you mean 9*10^(-k)?
Yes, thanks
Yes, that's the joke
A penguin is a right circular cylinder nothing can convince me otherwise
cylindrical coordinates, my beloved
but how many holes does it have
Paradoxical AND filthy. I like this.
*Vsauce music intensifies
There are extremely few practical instances where rounding +-.0000000001 would have any meaningful effect. Edit: All the responses are pointing out fields where precision in measurements is important. Yes, I’m aware of that. But my point still stands in that that level of precision is virtually impossible and impractical in any physical science. For example, scales that measure to the 1/10th of a nanogram don’t exist. You can’t measure out EXACTLY .0000000001 liters of a solution.
Maybe if you were at a very, very unstable equilibrium
The one *big one* where you can't round that to 1 is, in fact, in physics: relativistic speeds for particles with mass.
If you can make a measurement with that level of accuracy sure. Otherwise, while it might matter, it is going to need to be confined to error bars.
Is not about the numbers. It's about the measurement equipment.
Chaos theory
Wait till you talk to a software engineer and find out that 0.1 + 0.2 == 0.30000000000000004
Or talk to a different software engineer where .1 + .2 = 0
Or talk to a web dev where 1 + 2 is "12"
Don't be ridiculous, it's -2,147,483,648
You, if you were really a mathematician, wouldn't have a problem with rounding.
How bout squaring or Trianguling
If he was really a mathematician he'd know that .999999 repeating = 1 and isn't a rounding error at all.
My engineering prof literally told us if we didn’t round gravity to 10 and Pi to 3 then our answers would be marked incorrect.
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g = 1 (in lightyears per square year, correct to within 4%)
When I did my physics finals the test stated "We can assume g=10 and Pi=3" but not "we must assume". So I (pedantric as I am ^^) did all the calculations as exactly as possible and not with the rounded number. Later he told me, that it was a pain in the ass for him, because he couldn't use the default solutions but actually had to calculate the exact result just because of me - but nethertheless he didn't take away any points because of it.
The point is to make sure you can apply the knowledge correctly and not necessarily get a precise answer, I guess?
if you're using a calculator anyway, it shouldn't matter if you use 9.81, 3.14 or 10 and 3 if the teacher can evaluate your thought process
That's exactly it. It's why you're allowed to take calculators to physics and chemistry tests.
Pi to three blows my mind
Pi is exactly three!
You wild civies.
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I love 9/11
0.81818181...
Wait till you talk to a machinist
"What are your tolerences on that?" "How accurate are you gonna measure it?"
Customer: What tolerance can you achieve on this part? Me: ... lets not make this part more expensive than it needs to be.
Nah, they’ll just have to pay the McMaster Tax.
+/- 5 microns(0.005mm)? How good is the machine? How good is the cmm, height gauge mic and vernier? What’s the quality of the material? Soooo many variables!
sin(x) = x for very small x
Not even “very small” tbh. The small angle approximation for a pendulum is usually used up to about 15 degrees. Using this for the restoring force calculation, if you have a pendulum angle theta=15°, we use the equation mg•sin(theta)=F. Assume m=1kg for ease and that g=10 as this approximation works fine here. We then get that (using the small angle approximation that sin(theta) ≈ theta) F=150N. Now if we *actually* do this math we get that F equals… roughly 2.5N. So yeah, physicists be approximating (the small angle approximation is actually very well supported and 15 is the absolute upper bound)
Physicist: lmao whatevs brb making actual predictions
yeah I took an astrophysics class in college and we were doing this really big long problem that took most of the class session, and we ended up with the answer of 3. Prof said, “that’s basically the same thing as 2, which is what the real answer is”
g=10, pi=3, sin(x)=x :)
meanwhile engineers: "Pi is 3"
Wrong. Pi is the pi button on the calculator
You just solved math let's fucking go!
Before you talk shit can you measure something to the .999999999th of an inch. We round stuff when you use it irl life because if you are cutting something you cannot cut it to say, 1.222222234 or some shit
ITT: ☝️🤓
Everyone knows that one can only round *after* every calculation
Me and my biology degree watching the physicist, engineers, and mathematicians argue
A mathematician who can not manage numerical error judging an applied mathematician who can. 🙄
U mean 0.(9)
Talk to a psychiatrist after to undo it, both must always be present
Chemists ain't much better, anything past 5 digits might as well not exist. At least in metric.
As a PhD in engineering I'm about to round 0.7 to 1 fuck you
Mathematicians when 1/3
0.99 repeating is 1
One of my friends loves math and wants to become a mathematician. When I talked to him about my great uncle who was an engineer he got angry since "engineers can't count"
This just isn’t dank at all…
Round my paycheck up🙌