Woah, I didn't even expect an answer from such a big KZbinr, but you even made a video about my question. That's so cool. I have been troubled by this problem since the day we got taught exponential equations in high school. I've always wondered how to solve those when both exp() and ln() functions show up in the equation .Thank you so much! -Mark
@blackpenredpen3 жыл бұрын
Here’s the man!! I like this question a lot! So thanks for that!!
@deedewald17073 жыл бұрын
Elegant question yielded that elegant solution !
@Th3AnT0in33 жыл бұрын
@@blackpenredpen i have almost the same question: When a^x=log_a(x) and has only 1 solution.
@SPVLaboratories3 жыл бұрын
@@Th3AnT0in3 a=e^(1/e). if you want me to make a video about it i can do that
@Th3AnT0in33 жыл бұрын
@@SPVLaboratories omg you got it, what are the calculous i need to do to find this answer ? I tried it a few years ago and i failed but idk if i can solved it now because i'm better at maths (Sorry for "frenglish" btw 😋)
@MathAdam3 жыл бұрын
Note to self: Do not watch bprp before morning coffee. Brain now hurts.
@blackpenredpen3 жыл бұрын
😆
@aashsyed12773 жыл бұрын
@@blackpenredpen this video is freaking good i like you so much
@aryanabhilesh113 жыл бұрын
yeah dude now it hurts ssoo much......aaaaaaahhhhhhhhhhh
@wjshood3 жыл бұрын
I dont think Ive ever seen you enjoying yourself quite this much. The look of joy on your face when you got them to touch brought a smile to my face.
@8-P3 жыл бұрын
Would love to see a lecture on how the W function is derived and how it works
@mathmage4203 жыл бұрын
It's more of a place holder than anything. You need to use Newton's method to solve it.
@justinpark9393 жыл бұрын
He has an explanation on how it works on another video
@blackpenredpen3 жыл бұрын
Please see description for the video 😃
@8-P3 жыл бұрын
@@blackpenredpen Thanks alot! I searched on YT for it but it didn't show up somehow :) My fault for not looking at the description
@benedictspinoza10253 жыл бұрын
BPRP: It makes no sense how big this number is Expects something in scientific notation BPRP: 2.33 Confused pikachu face
@gabrielnettoferreira84523 жыл бұрын
Long live (in our hearts, at least) to the soviet union, the first great attempt to leave behind our pre-history!
@ieatgarbage87713 жыл бұрын
Well, he did draw the solution on the board at the start
@Kdd1603 жыл бұрын
Haha its funny to see the Lambert W Function pop almost in every bprp video!
@maxime_weill3 жыл бұрын
cool fact i just realised: applying a translation to exp is exactly like scaling it in the y direction, since e^(x-a) = e^x/e^a . Just like exponential transform addition into multiplication, it transform translations into homothety
@SpaceWithSam3 жыл бұрын
Such a joy to see you solving and explaining them with clarity, great job mate!
@blackpenredpen2 жыл бұрын
We will make b^x and log_b(x) tangent to each other here: kzbin.info/www/bejne/q37JgKaBjNesiZY
@andreiion63953 жыл бұрын
Watching this video before surgery, your math always brings me happiness and joy :)
@3ckitani3 жыл бұрын
Instead of shifting the graph, how about changing the base instead? Like what number "a" such that the graph a^x and log(a,x) touches?
@SabyasachiGhosh16183 жыл бұрын
Great question! It happens for a=e^(1/e).
@ManjotSingh-sf2ri3 жыл бұрын
@@SabyasachiGhosh1618 so the 'e'th root of e
@Logan_Roman3 жыл бұрын
Where we have a flat line and something imaginary?
@92ivca2 жыл бұрын
He did it today 😄
@tomileevasico57413 жыл бұрын
This is cool,that helps everyone who wants the subject math.
@nonono81083 жыл бұрын
1:21 [keep in mind] only 1 *REAL* solution!
@Melkboer383 жыл бұрын
1/W(1) + W(1) is equivalent but a bit cleaner in my opinion (you can show from W(x)e^(W(x)) = x that e^(W(x)) = x/W(x) and ln(W(x)) = ln(x) - W(x), plug in x = 1 to obtain e^(W(1)) = 1/W(1) and -ln(W(1)) = W(1).)
@deedewald17073 жыл бұрын
It's ALL relative !
@jayska58023 жыл бұрын
That was sick. Great work bprp
@VikashKumar-pj6bs3 жыл бұрын
One of the few channels which makes maths fun.
@mathsandsciencechannel3 жыл бұрын
great
@VikashKumar-pj6bs3 жыл бұрын
@Virat Kohli you can easily tell that from my name. BTW what's your name?
@abcd1234___3 жыл бұрын
Agreed
@SyberMath3 жыл бұрын
Nice! I did not know about the Lambert Function until I watched your videos! You're amazing! 🤩 Really cool topic. I had made a video on the intersection of y=e^x and y=kx but my wording was incorrect. I asked for the k value for only one solution to e^x=kx but my intention was "What is the k value if the graphs are tangent?" which has the same idea.
@sueyibaslanli35193 жыл бұрын
Finally, a real mathematic video after a long gap
@samuelromero17633 жыл бұрын
I like how it’s a simple question with a cool answer.
@michaeleiseman40993 жыл бұрын
A much more accessible problem (and I think more fun) is the following: Suppose we wish to find a base "a" such that a^x = log_base_a(x) at only one point. In other words, we want to find the exponential and log base that makes these two functions just touch one another at one tangent point. Using first-year calculus only, you will find that a = e^(1/e). COOL!
@Oliver-wv4bd2 жыл бұрын
From the relation e^W(1) = 1/W(1), you can also show that W(1) = -ln(W(1)), so the final answer can actually be written more simply as: a = W(1) + 1/W(1)
@carultch Жыл бұрын
What are the mechanics of how a computer calculates the LambertW function?
@hassanniaz75833 жыл бұрын
Amazing video as always! Great thinking by mark. Loved his idea.
@erik96713 жыл бұрын
Considering this was relatively easy, i wondered if it was actually solveable in a general case for moving in two directions (x and y), so: e^(x-a) = ln(x) + b Obviously this would generate a whole set of solutions itself, and ideally one could try to look for the minimum of this set in terms of "distance moved", i.e. minimum of c = a^2 + b^2, and i think this should give one (or mulitple?) Solutions. Turns out i am shit at math though so i got stuck in the process of getting a function nice enough to differentiate in terms of c. Just leaving this here in case any smart person comes around to this :)
@SPVLaboratories3 жыл бұрын
@Henry 1 yeah this is exactly right. you can do some insane Lagrange multiplier/Lambert-W manipulations to get the same thing but this is a good intuitive way to look at it
@92ivca3 жыл бұрын
I asked myself the same question. The solution is f(x)=e^(x-1)-1 and it is tangent to ln(x) in P=(1,0). I started in the same way bprp did: e^(x-a)-b=ln(x) same tangent so: e^(x-a)=1/x now, instead of explicating x, using the Lambert W function, we explicate a and b: b=e^(x-a)-ln(x)=1/x-ln(x) a=ln(x)+x so we have a^2+b^2=(ln(x)+x)^2+(1/x-ln(x))^2 deriving this function and setting the derivate to 0, we have a long equation that has only one real solution that is x=1. So we have: a=ln(1)+1=> a=1 b=1/1-ln(1)=> b=1
@erik96713 жыл бұрын
I see (@Henry 1, @92ivca) should have tried a few easy cases first lol. Would be cool to see someone tackle an actual analytical solution of this, but i think the math might actually melt my braincells.
@92ivca3 жыл бұрын
@@erik9671 the math isn't that hard, I edited my previous answer with a solution, but it doesn't shows all steps, because I ended up solving a very long equation
@erik96713 жыл бұрын
@@92ivca Oh i see, thats really not thaaaat long, thought thanks for the edit :) (I am an engineer and we generally take sin(x) = x as an approximation regarless of the angle, so math stuff that is pretty easy can sometimes fuck me up pretty badly)
@dylanl.33663 жыл бұрын
The final question for our univ entrance exam in South Korea 2 years ago was actually very similar to this question! It's very interesting that you happen to show this problem in your video today.
@MATHSEXPLORER13 жыл бұрын
Sir, how to solve this series problem: 5,7,17,55,225,1131, x , 47559 Find the value of x??? Sir, make the video on this topic please.
@abhid53003 жыл бұрын
I have also try but I didn't get answer. Can you tell me the answer?
@MATHSEXPLORER13 жыл бұрын
@@abhid5300 Ok , But first of all blackpenredpen give answer.
@mohansingh37503 жыл бұрын
@@MATHSEXPLORER1 Yes, I have try but it doesn't make any formula, please tell any hint.
wow. nice video. its nice solving challenging calculus questions of this sort and that is what i love doing on my...... thanks for checking t out
@madnessJATIN3 жыл бұрын
Congratulations 🎉🎉 sir for 700k , soon 1m
@Asterisk_7667 ай бұрын
Finally the Crossover we needed
@Twitledum93 жыл бұрын
Now we do e^x= ln(x+a)!
@Twitledum93 жыл бұрын
Actually, no need. ln(x+2.33) =e^x as we might expect and BPRP alluded to in the beginning. If you move both curves than there are infinitely many solutions right? Cool that x = 2.33 involves "omega" though 🤷♂️
@92ivca3 жыл бұрын
Next step: since the translation of e^x shown is only in x direction, find another translation (in both x and y direction) that minimize the translation length. (Hope you understand what I mean... Sorry for my bad english)
@92ivca3 жыл бұрын
SPOILER: Don't know if my math is correct but I found a really satisfying solution: e^(x-1)-1 that is tangent to ln(x) in P=(1;0) No Lambert W function needed to found this
@spaghettiking6533 жыл бұрын
@@92ivca Nice, how did you find that?
@92ivca3 жыл бұрын
@@spaghettiking653 same start, but with "a" and "b": e^(x-a)-b=ln(x) e^(x-a)=1/x Now we can explicate a and b (instead of x) a=ln(x)+x b=1/x -ln(x) We need to minimizing this: a^2+b^2=(ln(x)+x)^2+(1/x -ln(x))^2 Searching the zeros of the derivate of the function I found only one real solution, x=1
@deedewald17073 жыл бұрын
Excellent and elegant request !
@spaghettiking6533 жыл бұрын
@@92ivca Thanks, good work !
@davidb28853 жыл бұрын
I solved it differently: You shift along y=const. So I tried to find a horizontal which intersects the two graphs at points with a common derivative. For that I needed the derivatives with respect to y. So I solved the functions y(x) for x and differentiated for y resulting in 1/y and e^y. Setting them equal you immidiately find y=W(1). Now you simply plug that into the x(y) and immidiately get a. Or more elegant: Because the problem is symmetric under an y-x-switch aka when you mirror along y=x, nothing changes, you can instead ask yourself, by how much the ln needs to be shifted up. This way you skip the solving-for-x-step and the confusion it brings: So e^x=lnx +a -> d/dx -> e^x=1/x => x=W(1) => a=e^W(1) - lnW(1)
@zildijannorbs58893 жыл бұрын
e^(x^2+1) = pi^2x? Gosh, never let me become a math teacher, my exams would ruin lives
@renyxadarox3 жыл бұрын
You can also try to meet them by lifting up ln(x): eˣ=ln(x)+a
@icantseethe76803 жыл бұрын
Here’s a similar Challenge: A circle with center (2,6) and a radius of r is tangent to the parabola y=-2(x-6)^2 + 6 at one point. Find the value of r
@ijemand56723 жыл бұрын
That's easy
@antonhelsgaun3 жыл бұрын
@@ijemand5672 ok
@tanishqrulania99023 жыл бұрын
Is it ≈3.43905
@icantseethe76803 жыл бұрын
@@tanishqrulania9902 👍
@zzztriplezzz5264 Жыл бұрын
Explanation please?
@reussunased51083 жыл бұрын
I reminds me a question i had in a math exam in High school, where we had to find the smallest 'a' such that ax^2 = ln (x) only have 1 real solution . It took me a while to figure it out tbh
@Rolancito3 жыл бұрын
Interesting. Was wondering what if you move e^x to the right AND ln(x) upwards until they meet. In other words, for what shift a do e^(x-a) and ITS INVERSE ln(x)+a meet? The answer is simply for a=1, at x=1
@miruten46283 жыл бұрын
I can get to W(e^a) = e^(1/W(e^a) - a). I can see that a = 1 solves it, but can you solve it algebraically?
@Rolancito3 жыл бұрын
@@miruten4628 No... I tried for a while to no avail, got that solution just by inspection. In fact, Mathematica gave up on {e^(x-a)==log(x)+a, e^(x-a)==1/x} with both Solve and NSolve
@penguinpenguin-zm2mr3 жыл бұрын
If f(x) and f^(-1)(x) meet at some point, this point should be on y=x , isn't it? I'm not sure whether it always hold, but in this case, it allows problem to be solved easily. e^(x-a) = x && e^(x-a) = 1 = > x=1 => e^(1-a)=1 => e^(1-a) = e^(0) = > 1-a = 0 => a= 1
@nasekiller3 жыл бұрын
@@miruten4628 you are thinking way too complicated. the functions are symmetric to y=x, so they actually have to touch that line at their meeting point. you get the equation ln(x)+a = x with derivative 1/x = 1, which solves easily to x=a=1
@ThAlEdison3 жыл бұрын
Because of W's weird relationship with e, a can also be expressed as 2cosh(W(1))
@shadmanhasan42053 жыл бұрын
This is why I love using the Desmos graphing Calculator
@tedchirvasiu3 жыл бұрын
When even a mathemarical formula finally meets someone but you don't
@anakin073 жыл бұрын
I can’t believe I understood that. I’m not native English and didn’t have integrals in school yet. Your explanations are amazing❤️
@IIBLANKII3 жыл бұрын
Not going to lie, I understood everything until you slapped W in there.
@valemontgomery94013 жыл бұрын
I always wanted to figure this out, but didn't really know how. Thanks for doing this!
@uaswitch3 жыл бұрын
A mathematician's version of a meet-cute right here.
@Ze_eT Жыл бұрын
I did a similar solution that eventually significantly deviates: Instead of starting with e^(x-a) = ..., I stated that "As the derivative of e^x is itself, it can only tangent where ln(x) intersects with its derivative, thus we must find out where ln(x) and its derivative meet", leading to the same equation. There, I used e^() instead of ln() to eventually get to x^-1 e^(x^-1) = 1 which also ends up with x = 1 / W(1). Here, the steps change significantly. I instead calculated the y value of the intersection. This is quite simple, as I just inserted the previous x value into 1 / x: y = 1 / x y = 1/ (1 / W(1)) y = W(1) I then determined where e^x meets that y value. This required the identity that ln( W( x ) ) = ln( x ) - W( x ) e^x = W(1) x = ln(W(1)) x = ln(1) - W(1) x = - W(1) Finally, I determined the value a by using the difference between the two previous x values. a = W(1)^-1 - ( - W(1) ) a = W(1)^-1 + W( 1 ) While the solution looks different, it equals the same value as the one in the video.
@nasekiller3 жыл бұрын
its actually much easier, if you shift both functions. since the graphs are symmetric with respect to the graph of y=x, you can just shift them, so that they touch the line. that way you get a picture that is much more symmetric. and the equations are ln(x)+a = x, 1/x = 1, which easily solves for x=a=1 so you get e^(x-1) and ln(x)+1
@Bangaudaala6 ай бұрын
2:40 HE CANT KEEP GETTING AWAY WITH THIIS😭
@mrborn16373 жыл бұрын
i love that you're using version 5 of geogebra.
@toonoobie3 жыл бұрын
You didn't fully simplify a in the video as you could have written it as a = e^w(1)+ln(1/w(1)) a = e^w(1)+ln(e^w(1)) a= e^w(1)+w(1)
@NoName-eh8fz3 жыл бұрын
Or 1/W(1) + W(1) if you want. But his way of solving is the thing that matters. :)
@ActionJaxonH3 жыл бұрын
Paused and worked out on my own, and got it right a completely different way! Here’s what I did. I set a = z to make it a 3D surface, y=e^(x-z), then solved for z=f(x,y). I then changed y=lnx to be 0=lnx - y as a level curve constraint. Then I used Lagrange multiplier and gradients, and solved for λ. Unfortunately, there was no solution I could find by hand to lnλ=(1/λ) so I converted to (1/λ)e^(1/λ)=1 and used Lambert W to solve. After plugging in the solution for λ, which was 1/W(1), I found the shared normal vector of , intersecting at (1/W(1),W(1)) or about (1.763, 0.567). I then plugged those x,y into the z=f(x,y) function to get about 2.33 for the “z” distance, which is the “a” distance.
@MrFeast-l1d Жыл бұрын
Using a metal sledgehammer to break a piece of butter@IonRuby
@peterojdemark2 жыл бұрын
Lover your channel. An idea for a similar problem that could be interesting to see your solution for: Finding base b so that y=b^x tangents the related b-base logarithm y=logb(x) in one point.
@blackpenredpen2 жыл бұрын
Thanks! I actually recorded that video a few days ago. Here’s my Chinese version kzbin.info/www/bejne/fXW2Z4mNnMiIjtk and my English version will come out this week.
@peterojdemark2 жыл бұрын
@@blackpenredpen Great! Looking forward too it:)
@dhoom-z72213 жыл бұрын
Top ten greatest love stories 😂
@blackpenredpen3 жыл бұрын
😆
@polyhistorphilomath3 жыл бұрын
I prefer e^(x-a)-a. It’s not much of a challenge but they are parallel at x=0,1 It’s so much nicer geometrically.
@aronmaciel3 жыл бұрын
If we're talking simmetry, I preffer e^x - 1 and ln(x+1) it touches on (0,0) and is symmetric on the y=x line
@allenjonesstyles61122 жыл бұрын
@@aronmaciel 😂 nice one
@alexanderlea22933 жыл бұрын
engineer's watching: "wow so the answer is e! I did not expect that!"
@pojuantsalo34753 жыл бұрын
The inverse function of y = e^(x-1) is y = ln(x)+1, so they meet on the line y = x at point (1,1) where their derivatives also have the same value 1, but of course this isn't as cool as shifting only y = e^x to the right and dealing with the Lambert W function ordeal it causes.
@alessandronitti69413 жыл бұрын
Other than shifting e^x on the X axis we should find also the solution if we shift it on Y, so we have e^x - a rather than e^(x-a) always equal to lnx ofc
@Mark16v153 жыл бұрын
I knew bprp was talented, but now inverse-function matchmaker?!! Wow!!! Next, he'll be performing the wedding ceremony for the sine and cosine functions.
@shivansh6683 жыл бұрын
Loved this innovative manipulation 🧡
@asamenechbayissa5533 жыл бұрын
What if we move e^x to the right one unit and ln(x) up by one unit, e^(x - 1) is tangent to ln(x) + 1 and the post of intersection is (1 , 1)
@MathwithMing3 жыл бұрын
Interesting problem: how many solutions does the equation a^x = log_a(x) have, where a>0? The answer, which depends on the range of a, is very intricate!
@carultch Жыл бұрын
Interesting question. To solve it, we'd need to set up a second equation to solve for the two unknowns. This would allow us to solve for the special value of a, where a^x = ln(x)/ln(a) has exactly 1 solution. Greater than this, there are no real solutions, and less than this, there are two solutions. If these two functions touch just once, they will also have the same derivative at the point where they touch, because they will both curve away from each other. This means we set their derivatives equal. d/dx a^x = ln(a)*a^x d/dx ln(x)/ln(a) = 1/(ln(a)*x) Our system of equations becomes: ln(a)*a^x = 1/(ln(a)*x) a^x = ln(x)/ln(a) Solve both equations to isolate a^x a^x = 1/(ln(a)^2 * x) a^x = ln(x)/ln(a) Equate them to each other: 1/(ln(a)^2 * x) = ln(x)/ln(a) Cancel one factor of ln(a): 1/(ln(a)*x) = ln(x) Multiply: 1 = x*ln(x)*ln(a) This equation will have a real solution, when ln(x) = 1, and x = 1/ln(a). This means that our solution is the following: x = e a = eth root of e, which is approximately 1.445.
@carultch Жыл бұрын
Continuing with this example, there will be two solutions, until a = 1, in which case you will have a degenerate case of a vertical line intersecting a horizontal line, at just one point. You wouldn't be able to solve for that one analytically, as you would get an error when you attempt to do so. The vertical line is x=1, and the horizontal line is x=1. For values of a that are less than 1, there is always just one real intersection of the two curves, when the logarithm curve is mirrored about the x-axis. That one solution will follow the diagonal line of y=x, where y=a^x and y=ln(x)/ln(a) are the two equations being graphed. This continues until another degenerate case at a=0, again where two perpendicular lines appear to meet at the origin. Although they don't really meet at the origin, because 0^0 is undefined.
@axbs48633 жыл бұрын
Finally someone decided to update math
@mathevengers11313 жыл бұрын
Can someone clear my doubt at 1:58 Can we always differentiate on both sides. For example: x^2=ln(x) Now differentiating 2x=1/x x=1/√2 Which is not true. Another example: 2^x=ln(x) Now differentiating 2^x ln(2)=1/x x2^x=1/ln(2) x=W(1/ln(2)) Which is not true. So how we can know that you can differentiate e^x=ln(x)?
@geryz75492 жыл бұрын
the special case here is that we know the two function graphs both have the same slope (i.e. the same derivative) at the point where they touch
@mathevengers11312 жыл бұрын
@@geryz7549 thank you for clearing my doubt after 11 months.
@AlBoulley3 жыл бұрын
IF: a = ??? then: e ^ (x - a) = (e ^ x) - a (aka irrelevance of parenthesis) I solved what seems like a variation of the original question: how far to “lower” e^x so it can meet ln(x)?? After achieving the solution, I was forced into a brief pause. Then I had to “duh!” myself. And then, after another brief pause, I had to “whoa, cool!” myself. Still not sure if I was smarter before or after I solved the “other” case.
@aniketeuler64433 жыл бұрын
Very beautiful Steve sir keep uploading stuff like that Sir 😀
@lucastellmarchi19483 жыл бұрын
When you set e^{x-a} equal to \ln(x), how can you be sure that there is only one solution? e.g., if a were to be larger than the value we found there should be 2 values of x s.t. these functions give the same image at those values.
@catlilface3 жыл бұрын
You can simplify that equation since exp(W(1)) = 1/W(1) and ln(W(1)) = -W(1), so a = W(1) + 1/W(1)
@Mothuzad3 жыл бұрын
Would you be interested in calculating the minimum distance between these curves? Similar in spirit to what you did here, but the steps should be completely different. Off the top of my head, you'd apply the Pythagorean theorem to both formulas, giving each an independent variable, then find the minimum of the resulting 2D function with calculus.
@blackpenredpen3 жыл бұрын
Thanks for the comment. I forgot to put an old video on the minimum distance between e^x and ln(x) in the description. It is there now. 😃
@Mothuzad3 жыл бұрын
Interesting! I hadn't noticed that nearest points on two curves would have to have equal derivatives, but it makes sense. Using the method I described, I think you'd end up finding a zero for the difference between the two derivatives, which ends up being the same fact.
@Superman37891 Жыл бұрын
Or by inspection you could do a = e so that they meet at the point (e, 1)
@madhavapai43213 жыл бұрын
Why do e^(x-a) to shift e^x to the right? Why not (e^x)+a
@RandomGuy-bf8wq11 ай бұрын
The even more crazy thing about this problem is that a=2.33.... is the solution for making e^(x) - a tangent to ln x as well
@khaledajlouni64193 жыл бұрын
I want to ask you about solving the equation 1/x =ln(x) l took e for both sides and I divided by x taking the w Lambert function and take the reciprocal and I had a different answer why?
@wiseolman3 жыл бұрын
Yours is faster and gives the same answer. As he said in the video e^W(1)=1/W(1).
@khaledajlouni64193 жыл бұрын
@@wiseolman thanks I missed that
@wiseolman3 жыл бұрын
@@khaledajlouni6419 No problem. If you wonder why it is that way, it's really just the definition of the Lambert W function. x e^x = c implies x = W(c) Conversely, W(c) e^W(c) = c
@agr_ Жыл бұрын
You should do a part II problem where the function f(x) = ke^x touches ln(x)
@Sir_Isaac_Newton_3 жыл бұрын
bro safe distance
@renatotafaj15073 жыл бұрын
That was actually cool 😎
@blackpenredpen3 жыл бұрын
Thanks!
@laCOHSSA3 жыл бұрын
Really Cool ! And you have that the value of the functions in this point (χ=1/Ω) it's Ω and its derivates 1/Ω. Really Nice problem
@MichaelRothwell13 жыл бұрын
Any point on the graph of e^(x-a) has the property that y = y' so we get ln x = 1/x.
@dewman74773 жыл бұрын
This is like me talking and meeting myself in the mirror
@babajani35693 жыл бұрын
Amazing. Could you plz also give some STEP 3 questions a go. They are quite a lot more difficult and are more beautiful than the STEP 2 question than you attempted as well. There are some very beautiful one such as proving the irrationality of e etc.
@TonyEmil20113 жыл бұрын
The quantity "a" is subtracted from the quantity W(1) in the exponent Not the quantity e^(W(1)) so I think we should take the logarithm again for both sides so that "a" equals W(1) - ln(ln(W(1)))
@ahmedittihadhasib75463 жыл бұрын
Hi, we could move both the curves so that they touch the line x=y since ln and exp are inverses of each other. That could be a neat solution as well.
@kanitatewari76043 жыл бұрын
And if we take a>2.33 they intersect at two points
@deedewald17073 жыл бұрын
True to two points !
@jimschneider7993 жыл бұрын
This shouldn't be a surprise, but if a = exp(W(1)) - ln(W(1)), then by exponent rules, exp(x-a) simplifies to (W(1)/exp(W(1)) exp(x). In other words, the translation of exp(x) by a is equivalent to a dilation of exp(x) by exp(-a) = W(1)/exp(W(1)).
@matjazwalland9033 жыл бұрын
interesting thought. move the curve to meet at a point. But do they really converge? In terms of a curve from a two-dimensional graph, yes they are contiguous. But what happens when we look at this equation in a three-dimensional graph. Is it just an optical illusion because we use an X / Y graph?
@saniya11803 жыл бұрын
am I right ,Sir ln(X) +2and e^x also touch together and ln(X) +3 and e^x are intersect at two point.
@PhantomPhoenix14023 жыл бұрын
I have a doubt Lets say that for some x e^x and ln(x) touch each other e^x=ln(x) differentiating, e^x=1/x and equating both xln(x)=1 so e^ln(x)•ln(x)=1 Taking Product Log, ln(x) = W(1) So x=W(1) But since we know from graph that these 2 curves won't intersect why are we getting a real value for x...or have I done any mistake?
@kutuboxbayzan59673 жыл бұрын
i didn't watch your video, i think solution is a=w+1/w while w*e^(w)=1, its about to be 2.32 edit:Looks like my guess is true. The answer can simplify to w+1/w
@MessedUpSystem3 жыл бұрын
At this point I feel like this is Lambert W function the channel
@theimmux30343 жыл бұрын
Such a nice answer
@Penrose7073 жыл бұрын
I arrived at an identity of a = x - ln(ln(x)). e^(x-a) = ln(x) ln(e^(x-a)) = ln(ln(x)) x-a = ln(ln(x)) a = x - ln(ln(x)) The graph of a = y, y = x - ln(ln(x)) has a vertex at [e^(W(1)), e^(W(1)) - ln(W(1))]. e^(a) = e^(x) - ln(x) = y has a vertex at [W(1), e^(W(1)) - ln(W(1))]. I wonder if there is any relation?
@omarkr863 жыл бұрын
what about determining the shortest distance between the two curves and what are the two points of the straight segment?
@platformofscience97903 жыл бұрын
Dear sir ,I have a question:Why do we use e for natural log or normal exponential functions.can you help me,please?
@GammaStyleGaming3 жыл бұрын
It is named after Euler, the guy who discovered it. The number e is also called Euler's constant. I suggest checking out 3Blue1Brown, if you want to know how we get the value of e.
@platformofscience97903 жыл бұрын
I know that but I wanna know why do we use it.
@Lucsji3 жыл бұрын
Normal exponential functions are of base e because it's the only base with which you can have exp'(x) = exp(x). This property of exp(x) is one of the things that make it so special, because it allowed the simplification of very complex math. As for logarithms, they were actually used by mathematicians before the exponetial functions were widely adopted. A Scottish mathematician named John Napier wanted to find a way to make hard computations easier by transforming products into sums. For that, he came up with the "logarithm tables", which you can read if you know the property log(a×b) = log(a) + log(b). In the table that John Napier came up with, he used the logarithm of base e, because it was the simplest form to do so. In a way, they made it base e without knowing.
@Lucsji3 жыл бұрын
There are probably more details I ignored, but I hoped it helped.
@platformofscience97903 жыл бұрын
Surely it helped; Thank you for response like this,I appreciate it a lot,again thank you.
@jamiesonjones3 жыл бұрын
Everybody gangsta till bprp brings out a blue pen
@nishantkumartiwari12023 жыл бұрын
Calculating (-1/2)! by a method adopted by myself - Let's calculate C(n,1), of course it is n . Put n=1/2 so C(1/2,1) is equal to 1/2 apply formula of combination C(1/2,1)= (1/2)!/{1!(-1/2)!} . Now knowing 1/2! as √π/2 , equate both equations and hence we get value of (-1/2)! as √π . Incredible . Similarly we can calculate some more negative and fractional factorials . If you know this trick already, then this trick has been already discovered, but if no one knows this trick then I am the first to use this .
@johannchevrier70633 жыл бұрын
We also have a = W(1) + 1/W(1) which I think is beautiful than the formula given in this video (but as I said it is just my way to think). Good video btw 👏😉
@grezende40563 жыл бұрын
Its so intriguing the type of numbers that appear when we ask ourselves these stuff. Is w(1) transcendental?
@Nidhi-ks6rn3 жыл бұрын
if it had a solution it would be like 2 parallel lines meeting together...ROFL
@fizixx3 жыл бұрын
Since the answer is approximate, is there any issues with precision? In other words, if the two functions must intersect at exactly one point, what guarantee do we have that ~2.33 is sufficient to meet that criteria?
@yoav6133 жыл бұрын
Do you have any problem that you have no video related to it ?!
@warmpianist3 жыл бұрын
I have a follow-up question from this same equation between e^x and ln(x). What if instead we rotate e^x clockwise, what is the angle needed to rotate so that e^x will touch ln(x)?
@dilunk687 ай бұрын
Which points on e^x lnx are closest to each other? And what is the min distance.
@nandakumarcheiro3 жыл бұрын
This means that an exponential function and logarithmic function may be shifted rather translated along x 1,2.33 as oscillting jump over and discontinuity.The transfer from micro level to macro levels of amplifications giving a clue that the horizontal electronspin will be amplified as higher energy vertical type spinning and vice versa.Will this trnsformation producing surrounding magneticfield that produce super conductivity.The super conductive magneticfield oscillation split -up electrons typically to produce Cooper Pairs .The 1 to 2.33 BPPR jumps typically enhancing the superconductivity twisters by the oscilltating topological twins critical to produce superconductivity effect a high technology information that could be arrrived at from the mathematical analogy.