Dear all calculus students, This is why you're learning about optimization

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[@zachstar]

Hope you guys enjoy! Two things to mention here. 1) The video that explains the last method for the 'lost fisherman problem' is already up on patreon and will be out in just a few days from this one's release. 2) Most of these examples/stories actually came from 2 books I recently read and those are linked in the description if you want to learn more math/optimization.

[@Strafprozessordnung]

5 days ago?

[@theneongamer4957]

wait how is it 5 days ago

[@naswinger]

where can i find that video about the most optimal solution to the boat problem?

[@zachstar]

@@naswinger It's on patreon now and will be out on the channel in 3 days. And for everyone asking about how this comment was posted 5 days ago, videos are posted early on patreon (plus I need to make them unlisted in order to get approval from the sponsor).

[@zachstar]

@@user-ox3ov2qt5o definitely does, thought that was a given

[@lambdamax]

Ahhh eliminating your enemies while using the least amount of cannon resources

[@ililililili9726]

Then use the rest of the powder as fireworks to celebrate victory.

[@beoptimistic5853]

kzbin.info/www/bejne/joGmmHqKbqefqLM 💐

[@I_killed_that_beard_guy]

@@ililililili9726 😂😂

[@noop9k]

And they say war is bad..

[@matthewbarnes7650]

@@noop9k It is, because now a new generation hates you.

[@ronniesamaroo1775]

Put the boat in reverse dummy.lmao

[@y.z.6517]

Let's frame the question better: you travelled 100 km away from the shore. Suddenly, it becomes foggy, and a violent gust tilted your boat for an unknown angle. Your fuel tank is leaking, and the engineer cannot stop it completely. All communication stopped. Survive the day.

[@joelmiller2601]

Y. Z. Survive the day =/= Go back to shore

[@MegaKakaruto]

@@joelmiller2601 go back to shore == survive the day

[@joelmiller2601]

ninja lame Sorry; but no.

[@adi-sngh]

@@y.z.6517 Then there is a high chance that we go far and far away from the shore

[@GhostEmblem]

zach star: we can do better but I wont explain it me: aww zach: just kidding me: yay zack: but not in this video me: aww

[@abhijanwasti7991]

I think the solution is a spiral. Not sure tho.

[@Juhamakiviita2.0]

@@abhijanwasti7991 hmm i think you could start doing the 1km circle and then move to the 1.04km towards the end i did some drawing on paint and came to the conclusion that you do 1km circle normally until you completed 3/4 of it and then stop turning and move in a straight line -> 1 + 3pi/2 + 1

[@zachstar]

Gotta tease a little bit

[@Blox117]

turned off notifications, disliked, unsubscribed, unfunded, demonetized, and reported for child abuse

[@aasyjepale5210]

Oof

[@tedskins]

Optimization was one of my favorite parts of Calculus. I really appreciated how applicable it was to the real world

[@ChrisSutherlandPhys]

tedskins2000 same!

[@peasant8246]

same!

[@alonlev-shani1171]

same

[@ThErrandBoy]

!emaS

[@ThErrandBoy]

@FBI ! I'm not under arrest am I? 🤔

[@TheSam1902]

6:35 Delta fixed a triangle problem, how ironic Δ

[@JonDoe-uq1mk]

I wouldn't say that's ironic. It's just coincidental and funny.

[@beoptimistic5853]

kzbin.info/www/bejne/joGmmHqKbqefqLM 💐

[@user-lv6rn9cf8m]

Just recently got interested in math. Wish I had before. Like in school, everyone asked "why do we need to learn this?" and no one could ever answer. "Because you should". It's as if they tried their best to make it as uninteresting and boring as possible. Had someone talked about humanity going to Mars or like the golden ratio... what a difference it would have made.

[@covovker]

Yep. One of the failures about education is that teachers often can't communicate why is the thing important, or how it may be fun or interesting. I was never interested in biology for example, and yet I caught myself watch full series about evolution of life by Aron Ra right from the single cell organisms up to humans, and thats 40 something episodes 5-15 minutes each. Which is a far too much for a guy who is not interested in biology =)

[@braxtonclaflin1818]

I was the same way in high school but learned to actually think math is pretty cool. You can almost tell the future with it. For example, everybody places an x where they guess a ball is going to land where you would calculate it with math and predict it perfectly every time. The look on their faces when you accurately predict where EXACTLY that ball will land 10 times 50 times in a row.

[@gabrielbarrantes6946]

To be fair, you never asked yourself how a plain can fly, how a computer works, how wireless communications works, lack of curiosity is the main issue

[@beoptimistic5853]

kzbin.info/www/bejne/joGmmHqKbqefqLM 💐

[@macade2852]

@@gabrielbarrantes6946 I have done a ton of research into the current US education system and thought a lot about how to fix it and I can 100% definitively tell you that lack of curiosity is not at all an issue when first learning about these topics. School has a way of taking things you like and forcing you into the most uninteresting and uninspiring part of those subjects especially in the beginning. Talk to any child in grades 1st to 6th and you will generally find they like things like math. There are even alternate education systems that you can put children in right now that are completely driven by the child's curiosity as in they have no set curriculum and those systems have proven to even give better results than regular school on tests.

[@ChrisSutherlandPhys]

Dear calculus students, enjoy it while you can! Calculus was such a cool course and in my opinion the math only gets messier from here! Thanks Zach!!

[@pouzivateljutube2995]

Math always get messier as you progress.

[@haslan4885]

@@pouzivateljutube2995 It's called entropy 😁

[@JonathanPunti]

Differential equations is a relief 🥵

[@michealbay1290]

Damn things get bad after Fourier sequences... As for the Taylor's theorem and what not, it still doesn't penetrate my head.

[@karagi101]

Everything after 1+1 is messier.

[@lock_ray]

Very very fun boat problem, thank you! The best I managed to get was ~6.4 The strategy I came up with is: - go in a straight line for some distance r - draw the two tangents to the unit circle that pass through your current location, label them A and B - follow A until you're on the unit circle - follow the arc of the circle until your direction of motion is perpendicular to B - go in a straight line towards B The total distance in the worst case scenario is given by r + sqrt(r²-1) - 2arccos(1/r)+ 3π/2 + 1 The optimal solution is for r ≈ 1.16

[@zachstar]

This was really clever! Only thing I'm not seeing is where you got the 3arccos(1/r), the way I drew this out I'm getting that it would be 2arccos(1/r), assuming the worst case is where you barely miss the shore and drive in an arc until you reach basically where 3pi/2 is on the unit circle and then drive perpendicular to the shore until you hit it (which would be 1km). In that case you'd drive the entire 3pi/2 arc - 2arccos(1/r). Or maybe I just didn't interpret your method correctly.

[@lock_ray]

@@zachstar yep! You're right, shouldn't be doing maths at 12am I guess! The actual value becomes 6.4 then, at r≈1.16 oops

[@ElicePriyadarshini123]

This is super cool!!

[@sudheerthunga2155]

How do you actually come up with these amazingly cool solutions?...wow ...is it easier to come up with such knowing optimizations ? P.S. I have not yet learnt calculus ... probably will be learning them this year... ~ A sophomore (10th grade)

[@lock_ray]

@@sudheerthunga2155 for me it didn't involve much calculus, the key was to reimagine the problem as stretching a rope around a circle with a couple of extra conditions. It was a really fun process and not tedious at all. The calculus only came at the very end for finding the optimal angle, but there you might as well just plot the graph.

[@ryanfoley3002]

Hey man. I just wanted to thank you for the resource this channel is. At my high school we’re required to right a 4000 word essay on anything. I chose math and just had a bunch of trouble finding a topic within that. Thanks to videos like this I settled on optimizing baysean search theory. I honestly could not of done it without this channel and would of failed a class. Just wanted to say thank you

[@luciahumphreyoscoz6703]

ib xdd ?

[@RC32Smiths01]

This was definitely and exactly what I was suggesting. This absolutely makes for an awesome and informative series man! Keep it up

[@beoptimistic5853]

kzbin.info/www/bejne/joGmmHqKbqefqLM 💐

[@rafaellisboa8493]

I love these videos where you show the application of different kinds of math, I will be studying this this year and I'm so exited for it

[@beoptimistic5853]

kzbin.info/www/bejne/joGmmHqKbqefqLM 💐

[@dawalton7435]

For anybody curious about the answer to the minimum spanning tree question, the algorithm they use is called Kruskal's Algorithm. Essentially, they sort the distances and, going over the sorted list, connect any two currently unconnected nodes.

[@iliapachulia9012]

this is the first time I can say that graph theory helped me solve a problem in any circumstance other than school

[@amirhalloul]

3:28 Angry pacman

[@AlexM-xj7qd]

Yes

[@THEMRblackboy7thst]

i´ve benn watching this channel for the last 2 months and love it. Great job man. I really like your content. Keep the good work. Cheers.

[@hmzakhalid]

I never understood the use of calculus until i started machine learning, Everything makes sense now

[@TheyCalledMeT]

gotta love the idea to "drive a perfect circle" around your starting point before you went for about 1km trough thick fog .. xD

[@h00db01i]

move in a spiral pattern, so that the distance between the lines of that pattern (measuring at an angle that goes through the centre) never exceeds the view distance in the fog. you'll also find survivors that fell out of the boat, if they're lucky and you don't reach shore first

[@sajt6619]

also what i thought first, till he mentioned the "what if we go the 1km at an angle approaching 0" then i realise, ok we gotta think in maths, not practical reality

[@sagacious03]

Okay video! Thanks for uploading!

[@intfxdx]

Love this one. Sharing with my class (I'm a prof teaching calculus and physics). Best wishes Zach

[@drgatsis]

I started this channel to help my class. Thanks for the inspiration Zach.

[@vijaysubramanian2037]

As always, a job well done!

[@hardlyb]

One of my friends figured out how to find the Fermat point for math club in high school. One of the rest of us in the room (might have been me, but I think it was another kid) realized that you could take weights on strings and hang them through holes, and the stable point was the Fermat point. Bell should have hired a 10th grader to help them.

[@karankakkar3999]

9:18 Basketball was invented in 1891, so this problem from 1686 probably did not involve a basketball. EDIT: 11:10 nvm you got me there

[@joelmiller2601]

Watch the whole video before commenting.. Why don’t people do this more often?

[@senseof_outrage9390]

@@joelmiller2601 That's put me in my place... Now I'm off to watch the rest of the video...

[@ThePenisMan]

Joel Miller Thats like the teacher telling you to ask your questions after the lecture Like I’d even remember

[@bastion8804]

​@@ThePenisMan You probably have a note. Write your question and read it out if it's not answered by the end of the lecture.

[@ThePenisMan]

Bastion Barrick that is an incredible waste of paper

[@akeiai]

1:08 *solves by logic* Stop. Since it's day, the wind breeze should go to the land, I feel the air hitting my face, so it should be the other way right?

[@agarwalamit081]

Le joie de vivre is watching your fascinating videos!! Thanks!

[@rapex2729]

This is one video, I waitet for!!! More of optimization please! x3

[@brain0nfire]

Imagine if you used this ancient technology called a compass.

[@spartanwar1185]

Or better yet, just look for waves, they likely lead back to the shore

[@otheraccount5252]

Polar inversion.

[@thetimelords911]

@@otheraccount5252 Just remember which way is north before going out into the water. If, somehow, this happens, just go "south".

[@PanozGTR2]

@@thetimelords911 You clearly don't understand the concept of being lost.

[@turolretar]

*compbutt

[@ninokri]

I love this channel! Thank you.

[@xtra_kr1spy855]

This is awesome! Thank you!

[@2005kpboy]

Just half way into the video.. And I say awesome.. Keep it up , man

[@joelimbergamo639]

I love seeing my city Girona in a video in english!!! ty!!

[@bluryourfaceoff]

Am I high or does the first solution not account for travelling away from the shore?

[@lucastothej]

If you traveled away from the shore, then you would only have to travel half a circle to get back. The problem was concerned with optimising the maximum distance.

[@lucastothej]

@@Max-ww7iz But that case would never happen because the radius of your circle is the distance you travel before starting to move in an arc

[@alexnoman1498]

No both of you still don't get it. You can drive in *any* direction and hit shore with this method. You take your point of lostness as the center of a circle. Then you drive your recorded distance to shore or more in any direction, for example straight ahead. Now circle around, done. Try it with a piece of paper!

[@JohnDoe-yc6nm]

@@lucastotheju start 1 km away from the shore, lets say you move 1.04km further away from shore (at first looks like u made it worse), from there you make a circle with center point being ur starting point (that was 1km off shore, this is important - dont envision a circle with the wrong center point), you will hit the shore because 1.04km is longer than 1km and the circle diameter will be 2.08km, so even if u move exactly away from shore, it was still only 1km+1.04km. In this case u only travel half a circle anyway, so it's still shorter than other situations where u ended up close to the shore after your initial move.

[@zorkan111]

Pause the video at 2:49 and observe the black circle. It's a circle with the center point at the 1 km spot around which you're supposed to be sailing to find the coast. In this case, he drew a 1.5 km line towards the shore. However, notice that sailing 1.5 kn in ANY possible direction still lands you on that same circle.

[@JasonSantos21]

love your videos man!

[@saranshsaxena3956]

Very cool concept. Please keep making such videos?

[@phyarth8082]

6:41 Fermat point is shortest distance task, if you have extra variable let say bandwidth, minimum length is dominant, but bandwidth can change location point.

[@leathernluv]

I love videos like this. Now to learn calculus... As soon as I can afford it (both time and money.)

[@bene2132]

To find the Fermat Point isn’t that the same as drawing a line from each vertex so it is perpendicular to the opposite line for two vertexs then where the lines intersect that would be the Fermat point? Please answer

[@flowerwithamachinegun2692]

What you described is the orthocenter of the triangle and, sadly, it's not the point with the desired property.

[@black_wind2794]

i literally coded Dijkstra's algorithm just two days ago and it is fun to look at the result

[@BlueLightningSky]

I remember James Grimes on his old channel did a similar problem to the Fermat point with four locations instead. His solution was to use a soap film to simulate how it should look like.

[@shoshinsamurai7901]

@5:00 Also, if you had turned right like in the figure, don't start your circle turning left, turn right again. Much more efficient. You will reach in (half the distance-1.04) or whatever distance.

[@terryivinho3228]

Inspiring, thank you.

[@majesticwizardcat]

Voronoi diagrams could also help to solve minimum distance problems like the triangle one. Given 3 points as the example, the point were the three Voronoi regions meets is the point that has the minimum distance between all three. There is a similar problem were a company has N werehouses that serve a certain region of a city and you have to find the best way to split these regions. The solution is given by the Voronoi diagram. Anyway, thanks for the great video Zach, have a good one!

[@austinhernandez2716]

It was my favorite yet most frustrating part of Calc 1 in high school. I loved it's direct applicability. The ones I hated the most was like filling up a cone, determining the rate at a certain height

[@Romashka_Sov]

12:56 Certain triangles (BCD, BCF, EFJ, GHI and HIJ) just fill my heart with so much pain...

[@randomflexi8019]

For the airport communication probem is what you did with the equilateral triangles just finding the middle point of two edges? Or is it more then that? (Sorry for mistakes I didn't learn maths in english)

[@Samir_Zouaoui]

Calculus was my favorit math course after Linear Algebra . i really enjoyed Optimization problems .❤

[@alisapuskala1437]

Thank you for this video. Could you include links to the derivations in the basketball problem?

[@Sunnywastakentoo]

I have 2 videos asking this exact question in my recommended.

[@cheeseinmypocketsvelveeta2195]

thanks for the 24 sound effect

[@olutayosolana6013]

This is what I hope to learn in an msc in supply chain management

[@joeyd9998]

How is it going?

[@bulldozer8950]

You can slightly decrease the velocity for the basketball problem. This is only because a basket ball can hit the front of the rim and still go in. I don’t know how much but you could decrease it by a bur

[@wjrasmussen666]

Hi Zach. On optimization problems. How about variable situations like a factory making something out of a variety of parts, materials, etc. Does the optimization solution for something change under a different viewpoint.

[@user-zs8ep4nq7h]

Thank you

[@programinggrid967]

How you made these animations man thesr are very helpful:)

[@imqwerty5171]

I love your videos! :)

[@alexisidro]

Brings me so many memories. Why can't professors use these type of examples?

[@Kicksbruh]

Very ‘Presh Talwalker’-like, enjoyed it!

[@davethesid8960]

Thank you for such an informative video on why maths is actually useful! Now I can convince my friends too... 😁

[@robertcampomizzi7988]

Get out of my head! My Dad was an Engineer. I was thinking about this concept the other day. Thanks!!!!

[@CB-lh4ph]

in the boat problem how do you know that you circle is big enough to reach the shore at all? wouldn't the worst case scenario be that you end up going directly away from shore and your circle ends up being too small to reach it?

[@wadpigh]

Can’t determine what direction it came from, can draw a perfect circle. Nice!

[@tiffanymarrigold449]

Surely for the first puzzle your given solution only works if you go in the rough direction of the shore - if the random angle you choose is further out to sea, your circle no longer hits the shore?

[@CrittingOut]

Had a test on this recently good shit

[@hishamalkayed3236]

I think the lost boat problem can be optimized further by moving with a square path inside a (one kilometer circle plus some small distance.)

[@Matthew-wj1su]

Yup, but use a triangle instead of a square. The square inside the circle has a perimeter of 6.93 km and the triangle has a perimeter of 5.2 km, both are which are lower than the circle minimum distance of 6.995.

[@Yupppi]

I learned optimization and other than calculate the size of the structure built with certain prices of certain materials, I used it for calculating optimum stadium ticket price in a football manager game when I knew the current audience numbers, the current price and the size of the stadium. For maximum profit that is. But like for what wouldn't use optimization! But so we just assume that we can't see the shore until we're on the beach with the boat?

[@MsKelvin99]

was kinda hoping for something on parameter adjustment like the LM (levenberg maquardt)

[@chrismitchell4195]

Hi Zach Star, awesome video. I had a question about text books because I'm going to highschool soon and wanted to get ahead in math and science, so I was wondering if you could tell me how to find the right textbooks to learn a subject

[@zachstar]

When I'm looking for a good textbook for math/science class I usually search quora and reddit for that same question and I always find some kind of response. Often there are good amazon reviews but they can be misleading as well depending on how technical or rigorous you are looking for a book to be.

[@soonts]

About the lost fisherman, in nature similar problems often cause spiral shaped trajectories.

[@troyyoung8167]

Enjoyed watching something that might have some use.

[@thezyreick4289]

In the boat example, if you are entirely unsure of where shore is and the fog hinders vision, then why wouldnt the most efficient way back be to turn the boat exactly 180 degrees and travel that path 1.05 km then do the circle thing if you dont hit shore?

[@ronpearson1912]

This is so awesome

[@harleysuchiang4682]

How do you make your animations?

[@ayaan5540]

How does Ant Colony Optimization fit into the idea of calculus optimization? How would one attempt to compare different optimization algorithms?

[@force6144]

My shortest path I calculated is 6.45km for the whole journey, but I'm not sure about the solution being perfect (nor correct) so looking forward to your next video :)

[@peeyushawasthi5203]

I will say a great video to explain the basic concept of optimization

[@oliverdowning1543]

If you’re using the best value d for the boat would a polygon be better or worse?

[@Larry21924]

This is pure genius. I read a book with similar content, and it was pure genius. "The Art of Saying No: Mastering Boundaries for a Fulfilling Life" by Samuel Dawn

[@mitulagr]

I think better d is a d such that the integral of the path value (sum) is minimum rather than just the worst case path to be minimum

[@nawafspov1]

for optimization problems, LP can be put to use since that's what it's for.

[@theneongamer4957]

Do you know why we take a whole unit about vectors and how can we use them in the real world. Also great video as always please please keep on doing these types of videos

[@rinrin4711]

Before watching a solution. I ended up with this equation: S(x) = x(1+ 2pi - 2acos(1/x)). Solving for the minimum gives roughly 6.995... at x = 1.044... I think that's a definite improvement compared to 7.28... at x=1. *EDIT:* ok, 30 seconds passed, and he repeated my solution word by word. And it's not even the best one D: gotta try more. *EDIT2:* Before I watch further. I got another equation: S(x) = x + 2sqrt(x^2-1) + 2pi - 4acos(1/x), this one gives the minimum of 6.459.. km at x = 1.242... that's my second guess.

[@kingfreddy5268]

For the first problem: What i dint rlly get. What if ur going 1 km out on the sea? Like if i lost orientation it msy happen so how does it help me to make a circle

[@killereks]

Where is the video link for the solution to the first puzzle ?

[@harshitsrivastava7700]

please do reply when you get the link

[@Twitchi]

I too, was looking for the link..

[@zachstar]

It's not available yet! Will be out in 3 days and is available on patreon now.

[@Twitchi]

@@zachstar Thanks

[@AntL03]

booksc.xyz/dl/78506901/ac16a2

[@manuelm962]

Regarding the boat problem, what if you drove into the wrong direction, so not towards the shore, but away from it. Thereby ending up, say 2 kilometers from shore, thus not reaching the shore using the 1km circle. Is it just an assumption that the rough direction of the shore is known or am I missing something?

[@crimsy4937]

What software do you use to make these kind of videos?

[@anabellalloyd1935]

Any books you could recommend

[@ThePie_NedGreen]

I’m confused doesn’t the ship have radar and staff locating where the ship is at what time or whatever? I know math is great and all but I’m pretty sure sailor have like water maps and stuff.

[@saims.2402]

Isn’t the Fermat point thing called the circumcentre.

[@PanicGiraffe]

What about a fibbonaci spiral to get back to shore?

[@vladislavurumov538]

What if we decide to go further into the sea? Then we wouldn`t hit the shore, right? Am I missing something?

[@alexnoman1498]

Yes you are. We left an anchor with rope at our "Lost Point" and drive in any direction as far or further than our distance to shore. Now drive in circle. You will always hit the shore because a circle with radius equal or greater than the distance from shore will intersect with the shore, no matter what. You were thinking of taking our guess drive as center, but we take it as our start around the perimeter. The only thing to think about then is to optimize *how far* we drive in any direction. He always showed the worst case, which is bad for understanding the problem, granted.

[@kakalimukherjee3297]

4:04 whoa this graph looks like the angle of deviation vs angle of incidence graph for a thin prism. Even the equation is the same

[@mihailpetrovici5044]

On the boat problem: what if you go one direction 90° and back 180° isn't this more efficient?

[@oliviamillington8246]

Worst case scenario in the first example is continuing to drive away from the shore? Where the circle created does not hit the shore

[@darkrino8474]

Basketball ball problem is Projectile motion problem?

[@flameshard]

Does the solution of the lost fisherman problem have to do anything with a regular polygon like shaped path, which stops before the next edge collides with the first one?

[@zachstar]

Not that I know of. I should note that I found this example in a book and the author provided 3 methods (2 mentioned in this video), but there was no indication that even the third method (that will be discussed in the next video) was the most efficient so there could be something else for all I know.

[@kimaegaii]

So you're saying you'd putt he anchor down where you were at 1km out, and then go 1km out and in a circle around that anchor and you're guaranteed. But that if you made any small error ( the 1 plus 2 pi thing) then you'd miss the shore by a smidge?

[@crazyst3ve01]

you said you can't remember where the shore is. What if you go relative further out into the ocean, instead of towards the shore. Your area you will ancher around, and do a full circle will all be within the water

[@SeeMyDolphin]

You travel *at least* the same distance away from your anchor, as your anchor is from the shore. This will guarantee that you always hit the shore before completing a full circle. (e.g. your anchor is 5km away from shore, then travel *at least* 5km in any direction).

[@nakawung]

I just wrote my optimization exam this morning. Why didn’t I see this before then 😫

[@nativeafroeurasian]

2:18 what about waiting until the fog is gone?

[@AB95_vlogs]

@Zach what if boat 🚣 moves unfortunately in the straight directions. 🤔