Hardest Exponential Equation!

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Brain Station

Brain Station

Күн бұрын

Hardest Exponential Equation! Math Olympiad
If you're reading this, drop a comment using the word "Elon musk". Have an amazing day, you all are awesome!

Пікірлер: 538
@brain_station_videos
@brain_station_videos Ай бұрын
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@Vega1447
@Vega1447 2 ай бұрын
There is no Harvard entrance exam.
@kabulykos
@kabulykos 2 ай бұрын
It's really annoying how correcting misinformation on a site like this always causes its Algorithm to promote the misinformation more than your correction
@thekaliss1
@thekaliss1 2 ай бұрын
its called clickbait
@mightyoak11111
@mightyoak11111 2 ай бұрын
I thought to get accepted to Harvard one has to simply express support for hamas or any other jihadist terror group. 😂😢
@thadwuj668
@thadwuj668 2 ай бұрын
I bet the video creator pulled this from a qualifying exam and has no concept of what a QE even is...
@thovenach
@thovenach 2 ай бұрын
There is no vega1447
@robertanderson1043
@robertanderson1043 2 ай бұрын
I define the Skibbity Q function as returning x when applied to x^x. Therefore the answer is Q(25).
@brain_station_videos
@brain_station_videos 2 ай бұрын
Lambert W is fr 🥲
@robertanderson1043
@robertanderson1043 2 ай бұрын
@@brain_station_videos Lambert W and Skibbity Q are both equally real.
@WilliamGerot
@WilliamGerot 2 ай бұрын
x^x has too many discontinuities and is unable to be broken into branches as the Lambert-W function is.
@Nethuja_GunawardaneSL
@Nethuja_GunawardaneSL 2 ай бұрын
@robertanderson1043 I already made that function long ago and named it the mu function μ(x). So it's mine, not yours.
@budderman3rd
@budderman3rd 2 ай бұрын
​@@robertanderson1043Give me your rigorous definition and details of it. If not, get tf out.
@studentofspacetime
@studentofspacetime 2 ай бұрын
So basically, you didn’t solve the problem. You just gave it a name.
@Wutheheooooo
@Wutheheooooo 12 күн бұрын
Except you can calculate Lambert W function without any calculator now, it has a fomular, not closed form but you can approximate, it based on \ln x which can also approximate using newton's method. It is solved, you found a fomular to the solution.
@Wynb824
@Wynb824 5 күн бұрын
Not really, since for this kind of thing, you can't have a solution represented in elementary functions
@williamstraub3844
@williamstraub3844 3 ай бұрын
This is why I hate the Lambert W function! It's like saying "What is the solution to x = sin(37)? Why, it's arcsin(x) = 37." The W function is useless unless you have a calculator or Wolfram Alpha handy.
@brain_station_videos
@brain_station_videos 3 ай бұрын
That's true. But atleast we are able to find a numerical value.
@tkyk314
@tkyk314 2 ай бұрын
i think you can write your answer as an expression with a function
@adw1z
@adw1z 2 ай бұрын
I'm guessing you hate logs and exponentials and regular sines/cosines/tangents and square roots and reciprocals too then?
@JeanG-s9j
@JeanG-s9j 2 ай бұрын
I agree, its like if I could create my own function, lets say J(x^x)=x, then if x^x=25, the solution is x=J(25).
@TheMathManProfundities
@TheMathManProfundities 2 ай бұрын
​@@JeanG-s9jBut you wouldn't be able to get a value from that. It's more like x=√2. It had a value but you basically need computation to evaluate it to any significant level.
@SVMNSP6213YT
@SVMNSP6213YT 3 ай бұрын
i think it isnt log? the natural log(base e) is ln(x)
@3141minecraft
@3141minecraft 3 ай бұрын
You are right. log is base 10 logarithm and ln is the natural logarithm(the base e logarithn)
@shlok2444
@shlok2444 3 ай бұрын
I guess the solution is just to replace log be ln
@t-cc3377
@t-cc3377 3 ай бұрын
It was a notation error. At least the narrator said "the natural log".
@MD-kv9zo
@MD-kv9zo 3 ай бұрын
Apparently a lot of people(including my maths and physics teachers)do that even though it just gets more confusing. Log should be to the base 10 and ln to the base e.
@FundamSrijan
@FundamSrijan 2 ай бұрын
​@@t-cc3377jfnot error , difference . It's still heavily used for natural log in many places .
@StevenTorrey
@StevenTorrey 3 ай бұрын
This is the first time I have heard of the W Lambert Function. Though the procedure looks familiar.
@axumitedessalegn3549
@axumitedessalegn3549 2 ай бұрын
A better answer is 2.9632 and you can just do log(25)/log(x) in a graphing calculator and look for a value that is x=y
@tsolanoff
@tsolanoff 2 ай бұрын
It’s a bit confusing to require applicants to know advanced math (Lambert W function)which is supposed to be taught in higher education institutions
@user-ix9zu5es6j
@user-ix9zu5es6j 2 ай бұрын
1:20 sports
@math_solver_N
@math_solver_N 2 ай бұрын
EA sports to the game
@tunistick8044
@tunistick8044 2 ай бұрын
AHAHAHAHAHAHAHA
@7F0X7
@7F0X7 2 ай бұрын
what kind of mind do you have. You *MADE ME HEAR THOSE WORDS WITH THE EA ANNOUNCER'S VOICE, DANG IT!!!* @.@
@Krazykahaan
@Krazykahaan 2 ай бұрын
Nah, the guy def did it on purppse
@divyamkumar1339
@divyamkumar1339 2 ай бұрын
Can you please write ln(x) instead of log(x)? Natural log is not the same as log with base 10.
@CAustin582
@CAustin582 2 ай бұрын
In American academia, log is implied as being base e unless otherwise specified
@death704
@death704 2 ай бұрын
In the whole of calculus, we rarely use log with something else as base except for e
@edwolt
@edwolt 2 ай бұрын
​@@death704In my calculus course, when talking about natural log we used ln. But for some reason, in CS courses people used just log as meaning log2 when they could've be using lb, which is kinda confusing.
@Mk3737
@Mk3737 Ай бұрын
​@@edwolt yeahh I'm a high school student and generally we're aware of ln and log still we use log instead of ln cuz yeah we've to rarely use log with base 10 unless until specified in the question
@TechMoon-mz7fo
@TechMoon-mz7fo 8 күн бұрын
​@@CAustin582No, it is not. I have three Algebra books and two Calculus books, and the Common Log 'log' is base 10, ALWAYS, and the natural log 'e' is either 'e' or lnx, ALWAYS Fk what your smoking
@chouch
@chouch 2 ай бұрын
...or why you should not study maths at harvard, nor watch random videos that pretend to be of mathematical nature. What a waste of time.
@SachinGupta-h7y
@SachinGupta-h7y 2 ай бұрын
Are you in Harvard💀
@aurelianmasdrag2179
@aurelianmasdrag2179 2 ай бұрын
youre saying it like any random can get into harvard
@bakasteveuwu2822
@bakasteveuwu2822 Ай бұрын
I mean if you are studying this and don't understand something then this video is a great tutorial
@pizzaofdarkness4041
@pizzaofdarkness4041 2 ай бұрын
I definitely need to use this equation while shopping at the grocery.
@pbierre
@pbierre 2 ай бұрын
It's ~ 2.96322. There is a more modern, easier to understand approach based on successive approximation and iterative computation. All you need is a calculator with exponentiation function x^y.
@WilliamGerot
@WilliamGerot 2 ай бұрын
Ah and we find the computer scientist/applied maths person in the group
@Brigadier_Beau
@Brigadier_Beau 2 ай бұрын
I used estimation and managed to get that it would be close to but less than 2.965. I didn't feel like refining further.
@gergokarath5739
@gergokarath5739 Ай бұрын
Bruteforced in calculator 2,963219774895. It's pretty damn close :D
@pbierre
@pbierre Ай бұрын
@@WilliamGerot Do I detect a hint of "us vs. them"?
@WilliamGerot
@WilliamGerot Ай бұрын
@@pbierre Nah I just love the different approaches people take it adds positive diversity
@andrewy664
@andrewy664 2 ай бұрын
Hello, 2 errors here: (1) you cannot just apply an arbitrary (in this case -- even undefined) function to both parts of an equation without proving than you don't lose any root and don't introduce any new root; (2) the same, when author applies exponential function to both sides of the equation (particularly, x=0 becomes a part of the domain after this operation).
@maddenbanh8033
@maddenbanh8033 2 ай бұрын
I don't see the problem here, if he's only focusing on the reals then clearly he's only using the principal branch and secondly while you werent exactly clear, 0 was defined at the start
@Munnstery
@Munnstery 2 ай бұрын
Adding to the reply by madden. The lambert W function is defined. It was defined in this video and is taught at degree level.
@andrewy664
@andrewy664 2 ай бұрын
> clearly he's only using the principal branch ​ @maddenbanh8033 , it is not a problem in this particular equation, but it may be a problem in another expression. I consider this video it to be an educational one, so as a newbie I'd like to to see a precise and systematic approach here, not just a green way. Moreover, a student may get a penalty for not mentioning those facts and possibly introducing inequivalence. And all my initial points relate to the real numbers set only. @benmunn7481, the function is of course defined by itself, but not in the scope of this task. I've studied dozens of higher math disciplines for over 5 years, but have never heard aout it, so it's hard to say it is widely used here and there. My nitpick was that for some functions it is OK to do so, but for another we may lose equivalence during the solution. E.g. if we use f(t) = 0 instead of Lambert W function, we will end up with the solution that x may be any real number which is, obviously, an error.
@whiteeyesgamerright1954
@whiteeyesgamerright1954 Ай бұрын
Let's Introduce jee advanced
@PinoyRobots
@PinoyRobots 2 ай бұрын
how could I live without W Lambert Function ?
@brain_station_videos
@brain_station_videos 2 ай бұрын
cannot 💀
@donsimon2830
@donsimon2830 2 ай бұрын
Q: What's green and commutes A: An abelian grape
@KasyapH
@KasyapH 2 ай бұрын
3:43How do you calculate this?
@1-human
@1-human 2 ай бұрын
using numerical methods
@DrHyperionSun
@DrHyperionSun 2 ай бұрын
I would try Newton's method assuming z=W(ln(25)) and Derivating f(z). But this is because I am dumb, sure there are more pretty methods.
@latorredelreloj
@latorredelreloj 2 ай бұрын
W is a lesser known function but it is well-known enough for many mathematical softwares to have it as a built-in function
@tunistick8044
@tunistick8044 2 ай бұрын
Newton's method
@jaudatalhusen9049
@jaudatalhusen9049 2 ай бұрын
​@@DrHyperionSundisliked for low self esteem
@abuelovinagres4411
@abuelovinagres4411 10 сағат бұрын
I am amazed by te amount of extra steps only to reach a result without any explanation.
@BG-bq1qp
@BG-bq1qp 2 ай бұрын
2.9632 just do 2.5^2.5 and go up until you are above 25, then give it more decimals until you’re close enough
@wbytgaming2843
@wbytgaming2843 2 ай бұрын
2.96324
@thecompliationvideos4246
@thecompliationvideos4246 Ай бұрын
-Newton-Raphson method -formula: xₙ₊₁ = xₙ - f(xₙ) / f'(xₙ) -Initial guess: x₀ = 3 1. f(3) = 3ˣ - 25 ≈ 2 f'(3) = 3ˣ (ln(3) + 1) ≈ 56.66 x₁ = 3 - (2 / 56.66) ≈ 2.9647 2. f(2.9647) = 2.9647ˣ - 25 ≈ 0.0775 f'(2.9647) = 2.9647ˣ (ln(2.9647) + 1) ≈ 52.33 x₂ = 2.9647 - (0.0775 / 52.33) ≈ 2.96322 (practically solved already, but I continued until it converged for 6 decimal places, tedious but simple) 3. f(2.96322) = 2.96322ˣ - 25 ≈ 0.00013 f'(2.96322) = 2.96322ˣ (ln(2.96322) + 1) ≈ 52.16 x₃ = 2.96322 - (0.00013 / 52.16) ≈ 2.9632198 4. f(2.9632198) = 2.9632198ˣ - 25 ≈ 0 x₄ ≈ 2.9632198
@bakersbread104
@bakersbread104 2 ай бұрын
I think you should explain the Lambert equation for this to be educational at all
@Wutheheooooo
@Wutheheooooo 12 күн бұрын
He did, it is the inverse function of xe^x
@georgegrubbs2966
@georgegrubbs2966 6 күн бұрын
Natural log is written as "ln". "log" implies "log base 10"
@azizbronostiq2580
@azizbronostiq2580 2 ай бұрын
2:15 AAAAAAAH YES ! x is totally equal to e^log(x)
@az3224
@az3224 2 ай бұрын
Log(x) to the base e tells us what should be the power of e to get x For example log2 to the base e equals 0.30103 this means e raised to power 0.30103 is equal to 2 Similarly log x to the base e is the power to which e is raised to get x Therefore x =e^logx Hope it helps you 🙂
@azizbronostiq2580
@azizbronostiq2580 2 ай бұрын
@az3224 yeah but no. He should have written e as the base of the log and not only "log(x)" otherwise is completely falsz
@laplace-fourier
@laplace-fourier 2 ай бұрын
@@azizbronostiq2580 Some countries teach log instead of ln. (And it’s more satisfying to write)
@azizbronostiq2580
@azizbronostiq2580 2 ай бұрын
@@laplace-fourier yeah but it's still wrong
@laplace-fourier
@laplace-fourier 2 ай бұрын
@@azizbronostiq2580 Not really wrong, advanced people use that
@JUGNUMEHROTRANEETASPIRANT
@JUGNUMEHROTRANEETASPIRANT 2 ай бұрын
I solved it in my mind as follows : X ln{x}=ln[25] Or ==> e^ln{x} . ln{x} = 2ln[5] Therefore, x =e^W{2ln[5]}. [OBVIOUS WHY OR EXPLAINATION GIVEN IN THE VEDIO{about W function }]
@JUGNUMEHROTRANEETASPIRANT
@JUGNUMEHROTRANEETASPIRANT 2 ай бұрын
If one knows about W , it shall take him/her less than 1 min to solve it mentally , otherwise , one would make guesses{e.g here , x~3 is a guess}
@Nihalshanu22
@Nihalshanu22 2 ай бұрын
@@JUGNUMEHROTRANEETASPIRANToh genius over here
@JUGNUMEHROTRANEETASPIRANT
@JUGNUMEHROTRANEETASPIRANT 2 ай бұрын
@@Nihalshanu22 Thanks 😁
@Rone-q8v
@Rone-q8v 2 ай бұрын
Why are there so many logs? Are we building a house?
@samus88
@samus88 2 ай бұрын
The fuck is a Lambert W function?
@just-dl
@just-dl 2 ай бұрын
2.963 gets really close.
@itsmetanay
@itsmetanay 2 ай бұрын
2.9633 is approximately exact
@netanelkomm5636
@netanelkomm5636 2 ай бұрын
@@itsmetanay"Approximately exact" is a funny combination of words.
@labyrinth2646
@labyrinth2646 2 ай бұрын
⁠@@itsmetanay2.96322 is closer
@MUI_Noam12
@MUI_Noam12 2 ай бұрын
google says 2.963219774894 is close enough its a rounding error
@just-dl
@just-dl 2 ай бұрын
@ Professor Google was always over the top! 🤣
@Guidussify
@Guidussify 2 ай бұрын
Ok, but where do I find the value of e^W(log(25))?
@HottyHelen
@HottyHelen 2 ай бұрын
@@Guidussify I wonder the same thing, as far as I can see this isn’t a function like sin or log, there’s no however long formula to find W of a value. I doubt it’s a button on any calculator you can buy. So you need to either use an analytical approximation, numerical methods like Newton Ralphson or software that probably use that. I just used Excel’s goal seek facility.
@cdmcfall
@cdmcfall 2 ай бұрын
Iterative methods (brute force), mostly, or just run it through a Lambert W calculator. To evaluate this one, you would type in " e^(W_0(log(25))) " into the Wolfram Alpha search bar. Make sure you take a look at the graphs of y = x^x and y = 25. These sometimes have real solutions that aren't immediately obvious, as in the case of 2^x = x^2
@lanaforeal2588
@lanaforeal2588 2 ай бұрын
To find the value of \( e^{W(\log(25))} \), we can utilize the property of the Lambert W function, which states that if \( y = W(x) \), then \( x = y e^y \). 1. First, compute \( \log(25) \): \[ \log(25) = \log(5^2) = 2 \log(5) \] 2. Next, we find \( W(\log(25)) \). Since \( W(x) \) is the function that satisfies \( x = W(x)e^{W(x)} \), we need to express \( \log(25) \) in a suitable form for the Lambert W function. 3. However, we can also use the property: \[ e^{W(x)} = \frac{x}{W(x)} \] For our case, this means: \[ e^{W(\log(25))} = \frac{\log(25)}{W(\log(25))} \] 4. Since \( e^{W(x)} \) simplifies to \( x \) if \( x \) is of the form \( y e^y \), we conclude that: \[ e^{W(\log(25))} = \log(25) \] Thus, the value of \( e^{W(\log(25))} = \log(25) \). If you need a numerical approximation, it can be calculated as follows: \[ \log(25) \approx 3.2189 \] So the final result is: \[ e^{W(\log(25))} \approx 3.2189 \]
@lool8421
@lool8421 2 ай бұрын
just seeing the problem makes me think about using this function
@strangerfun7949
@strangerfun7949 Ай бұрын
Me :- hit and trial ( with common sense )
@Rise6474
@Rise6474 2 ай бұрын
Everyone in the comments are WRONG. The ACTUAL answer is: X = 2.96321977489346
@chrupek439
@chrupek439 2 ай бұрын
2.963219774893456328309^2.963219774893456328309 = 25.000000000000000000159053596577 so nope, still working on it i got to: 2.9632197748934563283059504789757^2.9632197748934563283059504789757 = 25.000000000000000000000000000001 my calc wont let me add more numbers 😂
@kateknowles8055
@kateknowles8055 2 ай бұрын
.....approximately..................................
@oAnshul
@oAnshul 2 ай бұрын
​@@chrupek439there's a decimal after 2 not a comma
@chrupek439
@chrupek439 2 ай бұрын
@@oAnshul in polish schools we are taught to use comma, for larger numbers we just leave space between every last three digits. But I changed it for you anyway :)
@SnowyPlayer
@SnowyPlayer Ай бұрын
The answer is irrational. The exact value is e^(W(ln(25)))
@cyruschang1904
@cyruschang1904 2 ай бұрын
x^x = 25 = 5^2 xlnx = 2ln5 let y = lnx, e^y = x ye^y = 2ln5 y = lnx = W(2ln5) x = e^(W(2ln5))
@Zeddy27182
@Zeddy27182 2 ай бұрын
The log(x) is not necessarily base 10. It depends on how it is defined! High school: base 10 College Math: base e Python, R, etc : base e CS : base 2 Even the definition of natural number varies: Math: 1, 2, 3, ... CS : 0, 1, 2, ... Overall, it really doesn't matter at all. "The essence of mathematics lies in its freedom." - Cantor
@cdmcfall
@cdmcfall 2 ай бұрын
ISO 80000-2, which is supposed to be international notation standards, says this: logₐ _x_ => logarithm to the base _a_ of _x_ ; standard, unambiguous notation ln _x_ = logₑ _x_ lg _x_ = log₁₀ _x_ => This was formally just log _x_ lb _x_ = log₂ _x_ log _x_ => This should only be used when the base does not need to be specified (most calculators treat it as log₁₀ _x_ while many apps, including Wolfram Alpha, treat it as ln _x_ )
@alexandreclergeaud4672
@alexandreclergeaud4672 2 ай бұрын
log is base 10, ln is base e
@aurelianmasdrag2179
@aurelianmasdrag2179 2 ай бұрын
0 is a natural number in maths
@adarsh-k5i
@adarsh-k5i Ай бұрын
@@aurelianmasdrag2179 really?
@syamprasad4455
@syamprasad4455 Ай бұрын
You can use newton raphson method to avoid look up table.
@Prime_Gamerzz
@Prime_Gamerzz 3 күн бұрын
double you 🗣🗣
@proking1033s
@proking1033s Ай бұрын
Its simple 2 power 2 is 4 3 power 3 is 27 Answer should be closer to 2.8 or 2.9 Thats how objective questions work
@xjz9264
@xjz9264 8 күн бұрын
between 2.9 and 3.0
@funprop9004
@funprop9004 Сағат бұрын
It also could just be √8.79
@livewithals
@livewithals 2 ай бұрын
Bit smaller than 3, that's what came first to my mind while looking at the equation.
@ilyashick3178
@ilyashick3178 2 ай бұрын
Solution is only in case by using natural logarithm. Log is not natural
@Idkhowtogeometry
@Idkhowtogeometry 23 күн бұрын
I thought the number was 5 and the exponent is 2 lol😅
@mohdabdulrahman2837
@mohdabdulrahman2837 5 күн бұрын
2.96322
@ivanmcauliff4597
@ivanmcauliff4597 19 күн бұрын
That would be the super-square root of 25, sometimes just called the "super root" of 25. No calculator that I know of has a super-root function - it's the one operation I know of that's actually easier to do on an ancient slide rule than it is to do on a calculator. We put the cursor hairline on 25 on the LL3 (e^x) scale. Then we move the slide bar left so that the right 1 is on that hairline. Finally, we move the cursor hairline to the left and try to find the point on the LL3 (e^x) scale where it matches with the point on the CI (1/x) scale. And that's roughly 2.96.
@thorliebhammer7238
@thorliebhammer7238 3 ай бұрын
Those who use "log" as the base e logarithm, are following the contemporary trend and are in the cool club.
@robertwarren4734
@robertwarren4734 2 ай бұрын
If you mean 'contemporary' as 1906. That construction is found on Boltzmann's tombstone.
@laplace-fourier
@laplace-fourier 2 ай бұрын
In my country, it’s common to use log and we also learn like that So, ye, I can agree with that
@foodymshmshinfomshart4000
@foodymshmshinfomshart4000 Ай бұрын
Answer will be 2.9633 by hit and trial method using calculator. Estimated time 3 minutes..
@strengthinnumberstutoring61
@strengthinnumberstutoring61 9 күн бұрын
To get into Har-VARD, I simply apply the “Become a Harvard Stu-…DENT” function! This takes input of “me” and returns “Har-VARD Stu-…DENT!” Quod erat faciendum.
@JonJenkins1982
@JonJenkins1982 2 ай бұрын
I figured it out in less time using a calculator and guessing and got more precision than the algebraic way
@maddenbanh8033
@maddenbanh8033 2 ай бұрын
He used an arbitrary amount of precision.
@wren51615
@wren51615 2 ай бұрын
I saw the thumbnail and knew it was a little under three, and thought “oh god is it eulers number again”. Glad it wasn’t
@elyesdimassi36
@elyesdimassi36 12 күн бұрын
approximately 2.963
@rangorhodeo
@rangorhodeo 13 күн бұрын
I would just take the calculator and do hit and trail of self multiplication
@RunItsTheCat
@RunItsTheCat 2 ай бұрын
Man Harvard really loves their Lambert W
@sanchellewellyn3478
@sanchellewellyn3478 2 ай бұрын
I know, right? But it's really useful. I just wish it were easier to calculate its values.
@nagendrababugalibu7322
@nagendrababugalibu7322 Ай бұрын
I know logarithms perfectly
@aksiiska9470
@aksiiska9470 18 күн бұрын
elon musk would say "3power3=27" and i am almost there
@highlyeducatedtrucker
@highlyeducatedtrucker 2 ай бұрын
Love the AI voice. "The Lambert double...(long pause)...u function..."
@moulibratasarkar841
@moulibratasarkar841 Ай бұрын
If you really just want approximate values, there are simpler solutions not using Lambert s w function
@odysseus9941
@odysseus9941 2 ай бұрын
Die Gleichung x^x=25 kann nicht mit einfachen algebraischen Methoden gelöst werden, da x sowohl als Basis als auch als Exponent auftritt. Stattdessen wird sie mithilfe von numerischen Methoden oder der Lambert-W-Funktion gelöst.
@yuki7951
@yuki7951 2 ай бұрын
I expected Lambert function to show up. I'm already used to seeing those videos XD
@louiscarl7629
@louiscarl7629 2 ай бұрын
Just put this in a solver that uses bisection, run some iterations and done, easy. Solves this whole class of thumbnail problems.
@Dr_piFrog
@Dr_piFrog Ай бұрын
Another mathematical solution video using (what I call the Willy Wanka function because of the plethora of KZbin trick videos requiring its application) the Lambert W-function.
@hardik-venturepiano1962
@hardik-venturepiano1962 2 күн бұрын
Lambert W function makes no sense to me. After all you HAVE to use a calculator to get your answer, Then why not just type in the equation and get your answer
@harikeshavraman5506
@harikeshavraman5506 2 ай бұрын
Obviously in modern world, we don't need this method to solve equations in daily basis - Excel Goal seek is going to help you out solve this one - Or if it's necessary to do it by a normal calculator, We know that the number and the power variable should be the same... 1^1=1, 2^2=4, 3^3=27.....so x is somewhere near to 3 in order to get x^x=25... Do some trial & error, Try with x= 2.9 & 2.95,gives value as 21.9 & 24.3...so raise x to 2.96, gets 24.84 which is closer... Try 2.965,gets 25.1....try 2.963,gets 24.98....final try with 4 decimals....2.9633,gets 25......Believe me guys this just took me 2mins to do! I work on these equations on a daily basis in my work and I always prefer doing trial & error methods.... For complex eqns, we can use some numerical int methods like Simpson rule, etc to calculate x sooner
@mohitp66448
@mohitp66448 2 ай бұрын
Literally did the exact same thing....
@odysseus9941
@odysseus9941 2 ай бұрын
Die Harvard University hat keine spezifische Aufnahmeprüfung wie z. B. eine standardisierte Prüfung, die alle Bewerber bestehen müssen. Stattdessen basiert das Aufnahmeverfahren auf einer ganzheitlichen Bewertung der Bewerbungsunterlagen, wobei viele Faktoren berücksichtigt werden.
@odysseus9941
@odysseus9941 2 ай бұрын
Die Harvard University hat keine spezifische Aufnahmeprüfung wie z. B. eine standardisierte Prüfung, die alle Bewerber bestehen müssen. Stattdessen basiert das Aufnahmeverfahren auf einer ganzheitlichen Bewertung der Bewerbungsunterlagen, wobei viele Faktoren berücksichtigt werden.
@Souf.df.90
@Souf.df.90 2 ай бұрын
For me , i never imagine a brut numer like 1 , i see wave and 1 in the top
@ЭльЯвор
@ЭльЯвор 13 күн бұрын
3**3 = 27 It is all you need
@netravelplus
@netravelplus 2 ай бұрын
Amazing problem, scaring in the beginning but as you started explaining, the fog cleared and the brain sparkled.
@hereticalgames3695
@hereticalgames3695 2 ай бұрын
Why people feel the need to solve using algebra over trial and error I’ll never understand.
@hereticalgames3695
@hereticalgames3695 2 ай бұрын
Edit: 5^2 =25 so the range must be 2-5 3^3=27 so the range is 2-3 punch in like 2.9 and you’ll find it short 2.96-2.97 is the next range how many decimals do you practically need. It turns into simple busy work fast.
@alexzuma2025
@alexzuma2025 Ай бұрын
the natural logarithm is written using ln. not log.
@ryanhollstein4164
@ryanhollstein4164 14 күн бұрын
Super square root of 25 which is a transcendental number
@niarai6898
@niarai6898 5 күн бұрын
Isn't it 5?
@maroly8342
@maroly8342 2 ай бұрын
The solution is between 2 and 3. No need to be more precise on that 😅
@laplacia
@laplacia 2 ай бұрын
(x^x)' = x(x^(x-1)) = x^x which makes its taylor expansion very simple.
@Antonio-v2j
@Antonio-v2j 3 ай бұрын
Me who thought it was 5^2 = 25 🥲
@brain_station_videos
@brain_station_videos 3 ай бұрын
thats why i mentioned it in the video 🤣
@just-dl
@just-dl 2 ай бұрын
That was my first thought then I attacked my calculator for the best approach: trial and error with guessing. 😎
@mathguy37
@mathguy37 2 ай бұрын
There's a different interesting way i found that appears to approximate a value without using the lambert W function so take the log of 25, the base matters to keep the number real, so just make a reasonable guess. Then just take the log of 25 with that as the base. Keep recursively doing that and the answer will approach the solution It takes a lot of logs to converge though, so it's easier to use recursive functions if inputting this into a calculator. (or using ans) 100 logarithms gives ~2.96321977726 with a starting base of 3, which is very close to the true answer. Any starting base within a reasonable range gives a nearly equivalent answer as the number of logarithms increase. Using 5 gives 2.96321987478. I couldn't figure out range of bases that work though
@jim2376
@jim2376 8 күн бұрын
x = e^W(ln 25) Then Wolfram Alpha x = 2.96321
@noobspidey8750
@noobspidey8750 9 күн бұрын
You could also do it with linear approximation right?
@viveksmenon123
@viveksmenon123 2 ай бұрын
i have no idea about lamberts function. If I just want to approximate, I can just do a binary search between 2 and 3. 2.5^2.5, 2.75^2.75, 2.825^2.825, 2.93^2.93, 2.96^2.96
@Slash1066
@Slash1066 2 ай бұрын
If its not 5 I'm all out of ideas
@saminyead1233
@saminyead1233 2 ай бұрын
Or, you can solve this numerically, since you know the answer is between 2 and 3.
@Dev-b4d6x
@Dev-b4d6x 8 күн бұрын
x is simply 5
@randerson4009
@randerson4009 2 ай бұрын
Why not just use an iterative approximation method on the original equation to the precision desired? This avoids the rearranging of the equation and finding the value of the resulting Lambert W.
@johnjr2jr2
@johnjr2jr2 2 ай бұрын
Nice. It makes a lot for the planet
@SuryaKant-u4h
@SuryaKant-u4h Ай бұрын
x^x can be written as x X x and 25 can be written as 5 X 5 So x is 5
@fomrehkuda
@fomrehkuda Ай бұрын
x^x cant be written like x • x
@shahabuddinansari9235
@shahabuddinansari9235 21 күн бұрын
Answer is approximately or may tell Answer is absolutely wrong
@Grassmpl
@Grassmpl Ай бұрын
Definitely get out your lambert W notation
@donsimon2830
@donsimon2830 2 ай бұрын
Have you heard the one about the mathematician and his logs. Well, he worked them out using a pencil.
@carloalbertocolaiacovo4182
@carloalbertocolaiacovo4182 2 ай бұрын
Bro you forget the modul inside the natural log when you do ln x^x = x ln |x| So you resolve that for x>o and for x
@b213videoz
@b213videoz 2 ай бұрын
Why do you keep calling log() with base 10 "a natural log" ?
@sohayb1m-582
@sohayb1m-582 2 ай бұрын
I actually found x 2.964 so im very proud of my self
@Boyscrazy719
@Boyscrazy719 2 ай бұрын
Harvard entrance exam 🤡 JEE Advanced ☠️☠️
@DailyWorkoutEnjoyer
@DailyWorkoutEnjoyer 2 ай бұрын
"And why do we need to know the answer to this?" ".. For...... uh... Science!"
@DeepakKumar-fi4gp
@DeepakKumar-fi4gp 2 ай бұрын
To solve the equation , let us proceed step-by-step: Step 1: Rewrite the equation We have: x^x = 25 \ln(x^x) = \ln(25) Using the logarithmic property , this becomes: x \ln(x) = \ln(25) Step 2: Approximation or numerical method The equation does not have a closed-form solution and must be solved numerically. Let's proceed: , so the equation becomes: x \ln(x) = 3.2189 Step 3: Estimate the solution Try values for : If , (too large). If , (close to 3.2189). The solution is slightly above . Step 4: Refine using numerical methods Using numerical tools (like Newton's method), we find: x \approx 2.559 Final Answer: x \approx 2.559
@АлександрБедин-х2ш
@АлександрБедин-х2ш 2 ай бұрын
What is the hardness of the task? If it is known in advance in which functions it is allowed to give an answer, then it is solved in 3 lines for any 9th graders.
@RyanLewis-Johnson-wq6xs
@RyanLewis-Johnson-wq6xs 3 ай бұрын
2^2=4 3^3=27 4^4=256 5^5=3125
@Why553-k5b_1
@Why553-k5b_1 2 ай бұрын
and? what is purpose of this comment?
@ronaldbryant5215
@ronaldbryant5215 2 ай бұрын
Calculators are not allowed - said all of my college math teachers.
@pingkai
@pingkai 2 ай бұрын
This is essentially saying we define the solution x^x = y and F(y), wtf.
@kateknowles8055
@kateknowles8055 2 ай бұрын
x = approx 2.96322
@eclxpse2
@eclxpse2 2 ай бұрын
Bruh just guess and check, i got x = 2.9634
@Esterified80
@Esterified80 2 ай бұрын
Absolute headache
@vatsalmakol7
@vatsalmakol7 2 ай бұрын
2.9634 approx
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