e^pi vs pi^e (no calculator)

  Рет қаралды 747,312

blackpenredpen

blackpenredpen

8 жыл бұрын

e^pi vs pi^e, which one is larger? We will use calculus, NOT calculators, to find out. This is a very classic math-for-fun a^b vs b^a exponential question. It is very suitable for all calculus 1 and AP calculus students. My approach is to find the maximum of the function f(x)=x^(1/x) by doing logarithmic differentiation, finding the critical numbers, and then doing the first derivative test. Watch to find out the final answer!
中文版(2021) 👉 • e^pi vs pi^e (外加兩個小故事)
The general case: a^b vs b^a 👉 • are you tired of the a...
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Пікірлер: 1 200
@MathIguess
@MathIguess 4 жыл бұрын
By the fundamental theorem of engineering, e = pi = 3. Both of those numbers are 27, which is approximately 30.
@Cream147player
@Cream147player 4 жыл бұрын
@Another Random Cuber Depends if you're making a legitimate calculation or just back of the envelope. For sure back of the envelope engineers do exactly this, because really you're just looking for order of magnitude. On a real calculation the engineer will use the exact value + 20% for safety, plus an extra 20% for safety on the final result of the calculation!
@anuj8825
@anuj8825 4 жыл бұрын
😂👌
@hatasesasd9631
@hatasesasd9631 4 жыл бұрын
Well, that looks like an approximation that would cause a lot of errors
@anuj8825
@anuj8825 4 жыл бұрын
@@hatasesasd9631 , its joke
@douglasstrother6584
@douglasstrother6584 4 жыл бұрын
... and 30 is "close enough" to 42.
@BizVlogs
@BizVlogs 7 жыл бұрын
Dude... this is dank. Mindblowing! But why are you holding a thermal detonator?
@blackpenredpen
@blackpenredpen 7 жыл бұрын
LOL. I have heard so many different nicknames for my mic and "thermal detonator" is so funny!
@bernardfinucane2061
@bernardfinucane2061 7 жыл бұрын
In case the proof doesn't work.
@harry_page
@harry_page 7 жыл бұрын
Because 50 thousand, no less
@alexwang982
@alexwang982 7 жыл бұрын
OOOOH its a mike
@karanabrol4487
@karanabrol4487 7 жыл бұрын
Exactly Pi hi exactly Tau /2
@japeking1
@japeking1 7 жыл бұрын
It makes me feel very strange to find myself at 2.00 in the morning really enjoying videos like this. Its not even that I really understand it.... I think I just enjoy watching someone being so enthusiastically clever. Thank you. Now I'm going to go try and sleep.
@lunam7249
@lunam7249 3 жыл бұрын
japeking1 mysteries of life....it’s enjoyable to see a thought a human mind solve a non trivial question.....logically....its bueatiful actually ..like the Mona Lisa painting...
@26IME
@26IME 2 жыл бұрын
Is the blank space... is ok I guess...
@NazriB
@NazriB 2 жыл бұрын
Lies again? EPA EPI
@equal7958
@equal7958 2 жыл бұрын
I'm seeing it at 1, four years later
@frostwobs
@frostwobs 7 жыл бұрын
There's actually another way Since e^x = 1 + x + x^2/2 +… by Macluarin series, e^x > 1 + x Then put x = pi/e - 1 e^(pi/e-1) > 1 + pi/e - 1 e^(pi/e) / e > pi/e e^(pi/e) > pi (e^(pi/e))^(e) > pi^(e) e^pi > pi^e
@matthewgrimm9036
@matthewgrimm9036 6 жыл бұрын
Beautiful!!!
@yeshwant5875
@yeshwant5875 6 жыл бұрын
Jonathan Ma loved it. I must congratulate you on this beautiful proof
@sonushaw1029
@sonushaw1029 6 жыл бұрын
Amazing friend I have a doubt how x^(1÷x) can't be zero. If we put x=0 we get 0^infinity and we know 0^(any number) is zero. 😕😕
@JamalAhmadMalik
@JamalAhmadMalik 6 жыл бұрын
sonu shaw x^infinity doesn't have an answer.
@cameodamaneo
@cameodamaneo 6 жыл бұрын
sonu shaw Watch this video. It doesn't explain your question exactly, but the thinking process is in the correct place: kzfaq.info/get/bejne/eLiCos98udKqZoU.html
@alxjones
@alxjones 7 жыл бұрын
Simplify the calculus immensely: x^y > y^x, log both sides and bring down the exponents to get ylogx > xlogy, then solve to get y/logy > x/logx, so the function to analyze is x/logx. We know x is bigger than 1 in both cases so we can ignore the asymptote. Derivative is 1/logx - 1/(logx)^2, and setting equal to zero gives logx(1-logx) = 0, so logx = 0 or logx = 1. Since x is bigger than 1, logx is bigger than 0, so logx=1 which means x=e. It's obvious that x grows faster than logx for large x, so the limit to infinity is infinity. Similarly, as x goes towards 1, the denominator goes to 0 while the numerator goes to 1, so the function goes to infinity. Thus, x=e is a minimum of the function, so e/loge = e is less than x/logx for any x>1, in particular, pi. So, pi/logpi > e/loge, so from the algebra in the beginning, we get e^pi>pi^e.
@ffggddss
@ffggddss 7 жыл бұрын
Very nice!!
@geneyoungdho
@geneyoungdho Жыл бұрын
Essence of Abstract analysis.
@xninja2369
@xninja2369 Жыл бұрын
I was going to write same thing bro
@technowey
@technowey 6 жыл бұрын
You solved that with e's (ease). It was easy as pi.
@joonah7316
@joonah7316 5 жыл бұрын
Goddamnit
@oxey_
@oxey_ 5 жыл бұрын
It was a piece of cake for sure!
@mikenotpike
@mikenotpike 5 жыл бұрын
r/iamverrysmart
@castroploiin
@castroploiin 5 жыл бұрын
SpeedyMicherGD r/whooosh
@mikenotpike
@mikenotpike 5 жыл бұрын
@@castroploiin r/ihavereddit
@Onyxyte
@Onyxyte 5 жыл бұрын
Nice proof without a calculator!
@sudipmaity8390
@sudipmaity8390 6 жыл бұрын
wow.what an amazing application of maxima minima concept.
@blackpenredpen
@blackpenredpen 6 жыл бұрын
Yay!!
@HummingbirdCyborg
@HummingbirdCyborg 7 жыл бұрын
I love your channel. It's been awhile since I took calculus and I enjoy how you use it to solve understandable problems. Keeps me refreshed.
@blackpenredpen
@blackpenredpen 7 жыл бұрын
I am glad to hear! thank you
@TakionMan
@TakionMan 6 жыл бұрын
I find your math videos quite relaxing to follow :) It's therapeutic.
@hughesyin9664
@hughesyin9664 5 жыл бұрын
e=3=pi, which means 3^pi =pi^e😂😂
@subscribetopewdiepie4109
@subscribetopewdiepie4109 5 жыл бұрын
Engineers be like
@alexbarac
@alexbarac 5 жыл бұрын
Funny thing: in astronomy this is actually correct, you're never concered about what's behind the decimal symbol but rather about the magnitude of the result. So 3*3=pi*pi=10
@methatis3013
@methatis3013 5 жыл бұрын
@@alexbarac 10?
@methatis3013
@methatis3013 5 жыл бұрын
@@alexbarac also, its 3^3, not 3*3. 3*3=9, 3^3=27
@alexbarac
@alexbarac 5 жыл бұрын
@@methatis3013 Yeah, it's an accepted approximation. In many cases you tend to get out of the equations pi*pi and to simplify the calculations, you just aproximate it to 10.
@REIDAE
@REIDAE 2 жыл бұрын
e=pi=3 both equal 27
@mrocto329
@mrocto329 2 жыл бұрын
e = 2 = 3 = pi
@gabrielscinteie341
@gabrielscinteie341 6 жыл бұрын
You can also demonstrate the inequality by using the monotony of the 1/x * ln x function
@ellelawliet8977
@ellelawliet8977 4 жыл бұрын
In a video of yours, you claimed and demonstrated that if a>b>e, then b^a > a^b. Both e^pi and pi^e are greater than e, so we can deduce instantly that e^pi > pi ^e because pi>e
@vanessamagnano6375
@vanessamagnano6375 Жыл бұрын
This is absolutely amazing! I had no idea you could use calculus to solve problems like this and I am mind-blown. Thank you for your videos and your channel 💙
@mohan153doshi
@mohan153doshi 6 жыл бұрын
What an absolutely awesome explanation! Just love all your videos.
@hanako_2137
@hanako_2137 5 жыл бұрын
Idk why but in this video the way you talk is relaxing af XD It's pretty relaxing in every video, but in this one it's at it's maximum
@blackpenredpen
@blackpenredpen 5 жыл бұрын
TheMichus Wow!! Ok!!!!! Maybe Bc of the music??
@hanako_2137
@hanako_2137 5 жыл бұрын
@@blackpenredpen I think this might be the case
@blackpenredpen
@blackpenredpen 5 жыл бұрын
TheMichus : )
@alkankondo89
@alkankondo89 7 жыл бұрын
Excellent video! You explain things VERY well!! Fortunately, I was able to figure it out after your statement at 1:46; that insight you gave was genuis! What I have found and love about math is that, often, the beauty comes, not in the answer or even the problem itself, but in the method used to find the answer and the creativity that such problems often require. Great presentation!
@blackpenredpen
@blackpenredpen 7 жыл бұрын
alkankondo89 thank you for finding my video enjoyable. I also have another playlist called the "math for fun" you can check that out too
@captainhd9741
@captainhd9741 3 жыл бұрын
@@blackpenredpen Sir how would you even have known that the maximum value of x^(1/x) is e^(1/e)? It is clear when we take the derivative but honestly I don’t see how anyone would even have thought of doing this in the first place to solve this problem.
@emiroercan
@emiroercan 3 жыл бұрын
@@captainhd9741 we have 2 statements as e^(1/e) and π^(1/π) and we want to find which one is bigger. İn those statements, different values are e and π so we just write x for them. Than we can make the graph of the x^(1/x) function and see the results. Or try to prove as he did in the video. We wrote x for them mainly because we don't want to calculate the result, rather we want to prove that one is bigger than the other. Also if we have a proper function, it's sometimes easier to find the extremum points rather then calculating.
@paolo6219
@paolo6219 3 жыл бұрын
Nice pfp
@iskrem596
@iskrem596 7 жыл бұрын
I like how great amd simple your explanations are and also how nice your accent sounds
@lnofzero
@lnofzero 7 жыл бұрын
Very nicely done! You have a very pleasant presentation style.
@seraphikimercury4921
@seraphikimercury4921 6 жыл бұрын
Dude, that's brilliant! I've been a math professor for 8 years and never seen such innovation. Where did you find such a question? Let alone the inspiration to solve it.
@medielijah
@medielijah 4 жыл бұрын
Sad Prof.
@ashwins1506
@ashwins1506 4 жыл бұрын
It's a JEE ADVANCED Question.
@rarebeeph1783
@rarebeeph1783 7 жыл бұрын
I have a better question. Which is bigger: key lime pi^e or apple pi^e?
@kingheathercapsicumannuum2840
@kingheathercapsicumannuum2840 5 жыл бұрын
Project Overturn aka RareBeeph apple pie^e is bigger
@elimarburger1659
@elimarburger1659 4 жыл бұрын
apple
@louisthurston3067
@louisthurston3067 6 жыл бұрын
I used e*ln(x)/x which is 1 at x=e and decreasing (take derivative) for x>e. So e*ln(Pi)/Pi
@tuerda
@tuerda 7 жыл бұрын
I had this problem on a calculus exam 14 years ago. It was interesting to see a youtube video that tackled it (and did so in a very different way from how I did it back then).
@chaosredefined3834
@chaosredefined3834 5 жыл бұрын
2.7 < e < 2.8 3.1 < pi < 3.2 e^pi > 2.7^3.1 > 3.2^2.8 > pi^e Therefore, e^pi > pi^e. No need for exact values. Just the first two decimal places of each (2.7... vs 3.1...)
@theimprudentman7272
@theimprudentman7272 Жыл бұрын
That doesn't make any sense in this world , how can u say that 2.7^3.1 >3.2^2.8 without calculator
@uwuowo7775
@uwuowo7775 2 ай бұрын
@@theimprudentman7272 just simply calculate it in the head !!!
@Mizar88
@Mizar88 7 жыл бұрын
beautiful! this proof is soooo satisfying!
@jlinkels
@jlinkels 7 жыл бұрын
Brilliant. Never saw an answer to this question before. And taking the derivative of x^(1/x) the way you do is very smart
@pachbentley
@pachbentley 3 жыл бұрын
Managed to do it by considering a^b and b^a where a>b. You can consider both scenarios and get a contradiction in a^b > b^a. Was very satisfying indeed
@vari1535
@vari1535 4 жыл бұрын
*starts using calculus on every question* Me: .-.
@hmxr715
@hmxr715 7 жыл бұрын
e to the pi is greater. I cheated..I used a computer.
@joelcoll4034
@joelcoll4034 6 жыл бұрын
You were a computer? How did you become a human?
@fastfingereveryday4237
@fastfingereveryday4237 6 жыл бұрын
Joel c.l what if he is a cat, not a hooman?
@SocksWithSandals
@SocksWithSandals 5 жыл бұрын
Mark Zuckerberg was an android, so you are in good company.
@SYFTV1
@SYFTV1 4 жыл бұрын
r/Not_cheating
@itsiwhatitsi
@itsiwhatitsi 4 жыл бұрын
Now are you human?
@Galileosays
@Galileosays 5 жыл бұрын
Taking double logarithm of pi^e: Ln(Ln(pi^e))=Ln(e.ln(pi))=1+ln(ln(pi)). Since 1+x < exp(x), we get. Ln(ln(pi^e)) < exp(ln(ln(pi)) = ln(pi). Taking exponent on both sides: ln(pi^e)
@akshettrj
@akshettrj 5 жыл бұрын
No need to take double log, take single log and one no. Will be negative other will be positive , the positive one will be greater
@charlesrambo7845
@charlesrambo7845 7 жыл бұрын
I've always wondered how to do this one! Thank you!
@blackpenredpen
@blackpenredpen 7 жыл бұрын
My pleasure!!
@mooncowtube
@mooncowtube 7 жыл бұрын
There's one final observation you could add here --- because x=e was the maximum, the other number didn't matter at all. e^x > x^e for ALL non-negative x except x=e. So e^2 > 2^e, e^420000 > (420000)^e, etc, and, of course, e^pi > pi^e. EDIT: inserted the word "non-negative" -- thanks all who pointed that out
@zyrohnmng
@zyrohnmng 7 жыл бұрын
as long as x > 0
@ffggddss
@ffggddss 7 жыл бұрын
To expand on zyrohnmng's comment: Need to avoid using negative numbers in such an example, because a negative number raised to a non-integer power is highly problematic, and almost always, non-real & multi-valued. And complex numbers do not have ordering.
@zyrohnmng
@zyrohnmng 7 жыл бұрын
That, and during his proof, he made the assumption that x was positive on multiple occasions for the very reason you just gave.
@mooncowtube
@mooncowtube 7 жыл бұрын
True -- I should have said ALL *non-negative* x except x=e, and not used -420000 as an example! (Note to +zyrohnmng: the relation holds ok for x=0)
@zyrohnmng
@zyrohnmng 7 жыл бұрын
The proof doesn't work for x=0 since the function and its derivative is undefined for x=0. You can check the case separately.
@jehooft8569
@jehooft8569 5 жыл бұрын
now this is e^pic
@johnrambo1988
@johnrambo1988 3 жыл бұрын
Where c=1, mind you.
@urfirasool32690
@urfirasool32690 5 жыл бұрын
Superb... Out of all your lectures this is my favorite😍😍😍
@danielbranscombe6662
@danielbranscombe6662 7 жыл бұрын
When I first saw this problem I used a similar approach but with y=e^x-x^e and using that you can prove that y>=0 for all x>0, with y=0 only when x=e. Thus you can say that for any x (obviously other than e) e^x is bigger than x^e and thus must also be true for x=pi
@muhammadhussainsarhandi9928
@muhammadhussainsarhandi9928 6 жыл бұрын
Sir, you teach in an excellent way, you cover those numerical which are neither present in any of the textbooks, nor they are taught by teachers in Colleges and in Universities. Sir can you please compare Phi (The Golden Ratio) with e and pi? I mean "phi to the e", "e to the phi", "phi to the pi", "pi to the phi", "e to the pi" and "pi to the e". Sir can you please compare them all together in a single video?
@blackpenredpen
@blackpenredpen 6 жыл бұрын
Thank you! The work will be very similar. The ones with base e will win. I think I can work out e^phi vs. phi^e for fun : )
@muhammadhussainsarhandi9928
@muhammadhussainsarhandi9928 6 жыл бұрын
blackpenredpen thank you for you reply Sir, but why are you so late in reply? I've commented on you "sine of 18 degree" video about a week earlier, I asked a question in that comment, but you havn't replied me,
@user-xi3kx3jq8s
@user-xi3kx3jq8s 5 жыл бұрын
مشكور جدا حل ممتاز
@divyoroy9056
@divyoroy9056 4 жыл бұрын
Muhammad Hussain Sarhandi lol
@muhammadhussainsarhandi9928
@muhammadhussainsarhandi9928 Жыл бұрын
@@divyoroy9056 what happened?
@alexandergarcia6479
@alexandergarcia6479 5 жыл бұрын
Thank you for helping me to remember first derivate test.
@Ksh3104
@Ksh3104 4 жыл бұрын
Take natural log for both sides and it's way more easier to differentiate if you take fx as x/lnx
@jayyyzeee6409
@jayyyzeee6409 5 жыл бұрын
That was a fun one! Thanks!!
@putinstea
@putinstea 7 жыл бұрын
for a^b > b^a, could you describe a function to give you the the upper limit of a for any value of b? in other words could the problem of e^pi vs pi^e be generalized to ANY real numbers ?
@TC159
@TC159 3 жыл бұрын
yes, and it was generalized in the video using the function x^(1/x). a^b > b^a iff e = a > b
@sitangshusekharbhattacharj2637
@sitangshusekharbhattacharj2637 7 жыл бұрын
r u crazy? e^x>1+x replace x by (pi/e)-1 answer obtained.
@sergiokorochinsky49
@sergiokorochinsky49 7 жыл бұрын
very impressive!... but this is just devine inspiration. I find his systematic approach a lot more useful.
@sitangshusekharbhattacharj2637
@sitangshusekharbhattacharj2637 7 жыл бұрын
thats true
@bahadr8021
@bahadr8021 6 жыл бұрын
Equation isn't correct for x=0 ?
@dasmarcy
@dasmarcy 6 жыл бұрын
@blackpenredpen
@blackpenredpen 6 жыл бұрын
Hi sitangshu sekhar bhattacharjee
@randellrussell2400
@randellrussell2400 6 жыл бұрын
Dude. I love your videos. I'm still learning algebra but I can't wait to be able to do these maths.
@captainhd9741
@captainhd9741 3 жыл бұрын
How’re u doing now?
@dreznik
@dreznik 5 жыл бұрын
as a corollary to x^(1/x) having a single maximum at e, we can generalize the result: for ANY x,y: x^y > y^x when either the triples (e,x,y) or (y,x,e) are in order, i.e.: (1) e
@dreznik
@dreznik 5 жыл бұрын
we notice that x^(1/x) falls faster from its maximum for x < e than for x > e, i.e., x^(1/x) is flatter right of e in case (3a) above, i.e., when x < e < y, can we show x^y < y^x when the x distance to the max (e) is bigger than the y distance to e, i.e., e-x > y-e, i.e.: 3a: if x
@indranathmukherjee6164
@indranathmukherjee6164 6 жыл бұрын
You are awesome.
@blackpenredpen
@blackpenredpen 6 жыл бұрын
Indranath Mukherjee thanks!!!
@a2333232332
@a2333232332 5 жыл бұрын
How about 2.001^1.999 vs 1.999^2.001
@charlesjones2122
@charlesjones2122 7 жыл бұрын
that is a very elegant and easy proof, thank you so much 😊
@VSP4591
@VSP4591 3 жыл бұрын
Very clever demonstration. Congratulation.
@diegoarend3281
@diegoarend3281 7 жыл бұрын
SUNDAY MORNING RAIN IS FALLING
@DarthChrisB
@DarthChrisB 7 жыл бұрын
That's one big ass microphone!
@Physicsnerd1
@Physicsnerd1 2 жыл бұрын
Excellent! I enjoyed that very much. Thank you.
@zhenyuanlu1764
@zhenyuanlu1764 4 жыл бұрын
Just consider the monotonicity of the function f(x) = ln(x)/x, since x^y > y^x i.e. ln(x)/x > ln(y)/y
@sithlordbinks
@sithlordbinks 5 жыл бұрын
I love how you solved it but you could just plug in the values to a calculator :P
@austingulotta9817
@austingulotta9817 6 жыл бұрын
Thank you. I was confident that pi^e would be bigger, and I'm glad to be humbled.
@MathsUnpluggedIndia
@MathsUnpluggedIndia 4 жыл бұрын
Yah but it's hard to predict between (1.23)^e and e^1.23? By intuition .. Calculus is crazy....it was created with intuition and it give solutions to problems which are not at all intuitive....
@johnrambo1988
@johnrambo1988 3 жыл бұрын
This is why you can't assume anything in math! Appearances are often deceiving
@elbisho2045
@elbisho2045 8 жыл бұрын
good proof, may you solve problems with conic sections please?
@spacetimemalleable7718
@spacetimemalleable7718 6 жыл бұрын
Very good logic! Excellent presentation.
@chasemarangu
@chasemarangu 7 жыл бұрын
I graphed them on my mac grapher app: y=e^x y=pi^x x=e x=pi and it turns out they are closer than I would've thought!
@rafaeldeassis3230
@rafaeldeassis3230 6 жыл бұрын
Sad about being on high school, i stopped understanding when he used calculus :(
@dekippiesip
@dekippiesip 4 жыл бұрын
@Sulayman Hussain the reason why implicit differentiation works is not that hard. It basically works because of the chain rule, keep in the back of your mind that y is a function of x ;)
@Anteater23
@Anteater23 4 жыл бұрын
Dy/dx (y) = d/dy(y) x (dy/dx) = 1 dy/dx = dy/dx You have always been implicit differentiating and you never realised. Every time you differentiate a y=___ equation. The LHS goes to dy/dx because of this reason.
@moontiger6393
@moontiger6393 4 жыл бұрын
Have a look at the essence of calculus series on the channel 3blue1brown
@rasheedmohammed2227
@rasheedmohammed2227 4 жыл бұрын
@Sulayman Hussain what you are saying is true. The fact that we can simplify differentials is not well defined in cal1 and cal2. With teachers telling us to pretend differentials as fractions. We don't get any concrete proof why until real analysis.
@awolgeordie9926
@awolgeordie9926 8 жыл бұрын
Excellent demo.
@ptirodaktill
@ptirodaktill 4 жыл бұрын
Is someone calculated at what point we can say that a^b>b^a ?. Seems like it work for every a>e and b>e .
@awseomgyhero
@awseomgyhero 7 жыл бұрын
I got an ad asking why I need to watch math videos from 2006 to do my homework...
@blackpenredpen
@blackpenredpen 7 жыл бұрын
The Epic Gamer I hate that ad too...
@Renegadezombies
@Renegadezombies 7 жыл бұрын
Wow, by choosing to do implicit derivation instead of the chain rule you made that derivative waaaaay harder than it had to be.
@blackpenredpen
@blackpenredpen 7 жыл бұрын
Brianna Baker waaaay harder? Please make it waaaaay easier for us. Apple sauce.
@Renegadezombies
@Renegadezombies 7 жыл бұрын
Okay I'll be honest, I forgot that using the exponential rule doesn't work for functions of base x, which is where I thought the majority of the optimization would come from. Still, it can be done without implicit derivation though apart from the first step this is fundamentally the same process you took. I guess I just hate doing implicit derivation unless it is absolutely necessary. Anyways here's the steps for those interested: imgur.com/a/sghux
@blackpenredpen
@blackpenredpen 7 жыл бұрын
-_-...... I was expecting something waaaaaay easier.......
@sacha7601
@sacha7601 7 жыл бұрын
easier solution: e^pi>pi^e ln(e^pi)>ln(pi^e) pi>e*ln(pi) pi-e*ln(pi)>0 let f(x)=x-e*ln(x). we want to prove f(pi)>0: f'(x) = 1-e/x so for (x > e) we have f'(x)>0 so we have f(x) increasing and f(e)=0 which means f(pi)>0. which means e^pi>pi^e
@sergiokorochinsky49
@sergiokorochinsky49 7 жыл бұрын
blackpenredpen... since you were expecting a derivative waaaaay easier, here it is: derivatives are just rules you memorise... like the product rule, similarly there is a power-exponent rule. For the product u*v the rule says "derivate u*v keeping u constant, plus derivate u*v keeping v constant". To derivate u^v "derivate u^v keeping u constant (exponential) plus derivate u^v keeping v constant (power)". Therefore d(u^v)/dx= u^v*Ln(u)*dv/dx + v*u^(v-1)*du/dx Using this rule (which is analogous to the multiplication rule) you can write the derivative in just one step. :-)
@shivani123cool
@shivani123cool 6 жыл бұрын
That was such a wonderful explanation...thankyou so much ...
@user-vs1yv5eg8m
@user-vs1yv5eg8m 4 жыл бұрын
I loved this!! you are awesome!
@serafeimzacharopoulos7862
@serafeimzacharopoulos7862 7 жыл бұрын
Great proof, nice job. But I think you should write the inequality : e^(1/e) > pi^(1/pi) > 1 . Only then you can raise both sides to the same exponent, which is pi*e, and be right with the inequality you finally get. In fact, this stems from the fact that the exponential function a^x is monotonically increasing for a>1, and monotonically decreasing for 0
@destroctiveblade843
@destroctiveblade843 7 жыл бұрын
well I think it's obvious since 1/e and 1/pi are positive they are both greater then 1
@LaTortuePGM
@LaTortuePGM 7 жыл бұрын
Destroctive Blade neither 1/pi nor 1/e are greater than 1.
@destroctiveblade843
@destroctiveblade843 7 жыл бұрын
of course they aren't but 1/pi and 1/e are positive so e^(1/e)and pi^(1/pi) are greater then 1
@serafeimzacharopoulos7862
@serafeimzacharopoulos7862 7 жыл бұрын
this is what you want to prove, right? My initial comment was aiming to the fact that the proof was incomplete, that's all.
@destroctiveblade843
@destroctiveblade843 7 жыл бұрын
yeah sure I just said that it is obvious
@anon6514
@anon6514 7 жыл бұрын
I sort of knew intuitively what the answer is but the beauty in math is seeing the proof :) wp.
@vinicus508
@vinicus508 4 жыл бұрын
Loved it. You are outstanding!!!
@poodlelord
@poodlelord 7 жыл бұрын
You are very good at explaining this stuff nice!
@wallaman
@wallaman 5 жыл бұрын
e^π and the π^e you like good p and I like the trees
@jardelkaique2522
@jardelkaique2522 5 жыл бұрын
Aren't they both equal to 9?! As all engineer knows, e = π = 3, so 3³ = 3³ = √81 = 9
@rsptouren9476
@rsptouren9476 5 жыл бұрын
Man, 3^3 is 27.😅
@s.h.kaifee9530
@s.h.kaifee9530 5 жыл бұрын
E is approximately 2.71828 whereas pi is approximately 3.14159
@lucifersdevilishdetails.
@lucifersdevilishdetails. 5 жыл бұрын
S.H. Kaifee and if you’re an engineer you round to the closest whole number and both e and π is 3 to their closest while numbers
@s.h.kaifee9530
@s.h.kaifee9530 5 жыл бұрын
Ohhh Getting smarter every day I didn't know that fact about engineers Thanks @@lucifersdevilishdetails.
@ebrahimalfardan8823
@ebrahimalfardan8823 7 жыл бұрын
Beautiful solution
@Pancake833
@Pancake833 7 жыл бұрын
wow, this was an incredible solution to watch. very inspiring, very cool :)
@blackpenredpen
@blackpenredpen 7 жыл бұрын
Evil MrMuffinz thank you!!
@jemcel0397
@jemcel0397 8 жыл бұрын
WOW!! I WORSHIP YOU IN THE SAME WAY AS I WORSHIP KHAN ACADEMY AND PATRICKJMT!
@blackpenredpen
@blackpenredpen 8 жыл бұрын
Thank you~! = )
@tigermoth8902
@tigermoth8902 8 жыл бұрын
Same this guy is amazing. Does mathematical hocus pocus to make hard problems easy.
@jemcel0397
@jemcel0397 8 жыл бұрын
+blackpenredpen was there a context like this in Stewart's Calculus?
@blackpenredpen
@blackpenredpen 8 жыл бұрын
Hmm, I am not sure..
@jemcel0397
@jemcel0397 8 жыл бұрын
+blackpenredpen it's okay! Anyway I hope you could do Calc III videos. Just a suggestion though.
@simonruszczak5563
@simonruszczak5563 7 жыл бұрын
Which one is bigger? I was told, size doesn't matter. The smaller one to the power of the bigger one.
@darrend.4835
@darrend.4835 7 жыл бұрын
Simon Ruszczak The problem is, the sizes do matter. If you, for example, have 3^2 vs 2^3, 3^2 is greater. This is the simplest example without using zeroes and ones (which would naturally mess things up), and it goes against the rule.
@andreyrumming6842
@andreyrumming6842 7 жыл бұрын
wouldn't 3^2 being bigger show that π^e be bigger ( pi~3 and e~2.6), which was proved otherwise?
@CHEH_tf
@CHEH_tf 2 жыл бұрын
bro that was so cool kee it up
@robertparada2838
@robertparada2838 7 жыл бұрын
But you can use if a
@VikeingBlade
@VikeingBlade 5 жыл бұрын
e^pi < pi^epi, so what? Where do you go from there?
@neverbackdown1918
@neverbackdown1918 5 жыл бұрын
I think it’s obvious that e^pi is greater than pi^e lol. Still, great video
@Larzsolice
@Larzsolice 7 жыл бұрын
If you just take natural logs, you get pi vs. e.ln(pi). pi is between 3 and 4 and e is between 2 and 3, so ln(pi) must be greater than zero but less than 1, and thus e.ln(pi) must be smaller than both e and pi. Converting back to exponents takes you back to the original form of e^pi > pi^e.
@sacha7601
@sacha7601 7 жыл бұрын
ln(pi) > 1
@quocanhnguyenle4952
@quocanhnguyenle4952 5 жыл бұрын
The natural log of pi is greater than 1 tho.
@Acleron
@Acleron 7 жыл бұрын
Very clever and great explanation.
@claudeabraham2347
@claudeabraham2347 4 жыл бұрын
Very good! Thanks!
@MrYoung-ty4hn
@MrYoung-ty4hn 6 жыл бұрын
Let's say e=2 and pi=3 2^3=8 3^2=9
@dasmarcy
@dasmarcy 6 жыл бұрын
gotta love physicists
@trayto100
@trayto100 6 жыл бұрын
quik maffs
@shrirammaiya4381
@shrirammaiya4381 6 жыл бұрын
Mr. American man that’s a bad estimate 😂
@SamirBenaissa_is_awesome
@SamirBenaissa_is_awesome 6 жыл бұрын
but e^pi is greater
@sultanelshirazy8184
@sultanelshirazy8184 5 жыл бұрын
Wow same method bro, but wrong estimation, it supposed to be e = 2.5 π = 3
@naimy4511
@naimy4511 4 жыл бұрын
That was e’s (easy) as pi.
@tristanlj3409
@tristanlj3409 4 жыл бұрын
That was e'asy pieasy
@joachimolsson9497
@joachimolsson9497 8 жыл бұрын
Amazing video :)
@notcyndi
@notcyndi 7 жыл бұрын
e^pi > pi^e. Because both of them are >= e. This is true for ANY 2 numbers that are >= e; if e
@peppybocan
@peppybocan 7 жыл бұрын
you derivate ln(y) by dx ...
@enzila468
@enzila468 7 жыл бұрын
yea, you can do that so long as you leave the dy/dx at the end.
@tintom3t
@tintom3t 7 жыл бұрын
Yes since you know that y is a function of x you evaluate it as such. By using dy/dx
@LordAmerican
@LordAmerican 7 жыл бұрын
Yes. It's called *implicit differentiation* because the derivative of y is derived implicitly.
@abiedarkhamilhami2663
@abiedarkhamilhami2663 7 жыл бұрын
Peter Bočan by using chain rule, we have: (d/dx)(ln y) = (d/dy)(dy/dx)(ln y) = (d(ln y)/dy)(dy/dx) = (1/y)(dy/dx) isn't it?
@kyledean1966
@kyledean1966 7 жыл бұрын
Or you could just estimate with 2^3 vs 3^2
@LaTortuePGM
@LaTortuePGM 7 жыл бұрын
ENGINEER DETECTED
@user-ms9sh2ed5v
@user-ms9sh2ed5v 7 жыл бұрын
that wouldn't have worked, since 2^3>(pi-3)
@letao12
@letao12 7 жыл бұрын
La Tortue PGM LOL That's exactly how I guessed my answer (I got it right using a slightly better estimate). And I am an engineer.
@davidprochazka3709
@davidprochazka3709 7 жыл бұрын
well, I did it for 2.7^3.1 and 3.1^2.7 and it worked
@LaTortuePGM
@LaTortuePGM 7 жыл бұрын
btw mathematical mathematics memes is the best fb group ever
@terapode
@terapode 7 жыл бұрын
FANTASTIC... What a great video!
@blackpenredpen
@blackpenredpen 7 жыл бұрын
Thank you!
@terimummymerihojaa
@terimummymerihojaa 3 жыл бұрын
I solved this with one simple observation i.e. a^b > b^a (when a π^e
@JiveDadson
@JiveDadson 7 жыл бұрын
That was going around when I was in math grad school in the early '70's. My solution was *_a lot_* simpler than yours. :-)
@blackpenredpen
@blackpenredpen 7 жыл бұрын
JiveDadson but I have more KZfaq views tho! :)
@astolfo9377
@astolfo9377 7 жыл бұрын
JiveDadson Fucking rekt
@matheuscardoso1
@matheuscardoso1 7 жыл бұрын
Nice work, bro! Well explained, you could be an excellent teacher.
@blackpenredpen
@blackpenredpen 7 жыл бұрын
Matheus Cardoso Thanks. I have been a teacher for many years already.
@ayushbanerjee4442
@ayushbanerjee4442 6 жыл бұрын
Classic teaching sir Lots of thanks
6 жыл бұрын
Can you do the proof e < pi? I can't seem to formulate one. Thanks in advance.
@carultch
@carultch 2 жыл бұрын
You can prove that pi lies between 3 and 4, by bounding the number with a hexagon on the inside of a circle with a diameter of 1 unit, and a square on the outside. The distance across opposite vertices of the hexagon equals the diameter of the circle. The side length of the square equals the diameter of the circle. The square's perimeter is 4 units, and the hexagon's perimeter is 3 units. This means pi is between 3 and 4. You can prove that e is between 2 and 3, by using the infinite series expansion that defines e e = sum of 1/k! from k=0 to infinity = 1/0! + 1/1! +1/2! +1/3! etc The first two terms are positive 1, and when added together equal 2. Since the remaining terms are all positive, this gives us 2 as the lower bound. To prove that e 2*2 for 3, 2*3*4 for e < 2*2*2 for 3. This means every subsequent term after 1/1! will be less in the series expansion for e, and therefore add up to less than 3. This shows that e is
@mircoberner9528
@mircoberner9528 3 жыл бұрын
much easier: e^pi > pi^e amounts to pi/ln(pi) > e = e/ln(e). take the function f(x)= x/ln(x); then is f'(x) = (ln(x)-1)/ln^2(x) so f'(e) = 0 with f'(e+h) > 0 > f'(e - h) for 0 < h < 1, which implies e = f(e) < f(pi) = pi/ln(pi)
@toferg.8264
@toferg.8264 6 жыл бұрын
Dang! That was awesome!
@MrConverse
@MrConverse 5 жыл бұрын
Outstanding!
@sandyvu9652
@sandyvu9652 Жыл бұрын
You're sooo smart for this planet lol I like the way you show us your passion for math👍
@Wutthehel0
@Wutthehel0 2 жыл бұрын
A beautiful, simple to understand and elegant proof. I'm a grade 10 student. But I understand calculus because of you! I literally jumped when you proved the maxima value :D
@Sh4dowbanned
@Sh4dowbanned Жыл бұрын
You can compute. Use the ceiling function. e^π is greater. π ≈ 4. e ≈ 3. π^e ≈ 4³ = 64. e^π ≈ 3⁴ = 81. 81>64 e^π > π^e 3:52, 4:19 24-Minimal maximum? So u take the derivative? 4:39 5:09: so, implicit?
@JackRule16
@JackRule16 3 жыл бұрын
I think a sort of incomplete "soft" proof can arise by really simple deduction. If e^e = e^e, 1^2 < 2^1, and 3^4 is > 4^3, then it seems logical that as long as both numbers are >= e, the term with the lower base is greater. Again I know this isn't complete but it's really easy to understand.
@Titurel
@Titurel 8 жыл бұрын
Great videos!! any chance of set on Fourier Transforms??
@blackpenredpen
@blackpenredpen 8 жыл бұрын
Sorry... I am not teaching that anytime soon.
are you tired of the a^b vs b^a questions?
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