how is i^x=2 possible?

  Рет қаралды 281,832

blackpenredpen

blackpenredpen

Күн бұрын

Пікірлер: 413
@blackpenredpen
@blackpenredpen Жыл бұрын
Learn more complex numbers from Brilliant: 👉 brilliant.org/blackpenredpen/ (20% off with this link!)
@ayoubbenchetioui6481
@ayoubbenchetioui6481 Жыл бұрын
pls Can 2^x=0 in the field of complex num ?
@icecoffee3485
@icecoffee3485 Жыл бұрын
@@ayoubbenchetioui6481 x is negative infinity
@ChavoMysterio
@ChavoMysterio Жыл бұрын
Please solve this equation: (-2)^x=2 Thank you
@Mnemonic-X
@Mnemonic-X Жыл бұрын
Where can I apply this useless knowledge?
@govcorpwatch
@govcorpwatch Жыл бұрын
We need more τ. e^-(τ/4 + nτ).
@debtanaysarkar9744
@debtanaysarkar9744 Жыл бұрын
I really love it when you say, " I don't like to be on the bottom, I like to be on the top"🤗🤗🤗🤗
@b_atanassov
@b_atanassov Жыл бұрын
🤨
@thexavier666
@thexavier666 Жыл бұрын
A very normal, totally not suspicious, comment
@stefanalecu9532
@stefanalecu9532 Жыл бұрын
🤨📸
@noreoli
@noreoli Жыл бұрын
@@thexavier666 yea absolutely, no complications there right? 🤨
@debtanaysarkar9744
@debtanaysarkar9744 Жыл бұрын
@@noreoli true, no complications 👌👌👌
@AyberkDurgut
@AyberkDurgut Жыл бұрын
Complex world is crazy.
@zeroo8756
@zeroo8756 Жыл бұрын
I wil be find new world Name is fantastic number
@Begubut2
@Begubut2 Жыл бұрын
By saying crazy, you are underestimating the craziness of complex numbers.
@mehmetalivat
@mehmetalivat Жыл бұрын
Gerçekten bu inanılmaz. Kuantum mekaniğinde de çok önemlidir.🙂
@tusharjawane9056
@tusharjawane9056 Жыл бұрын
I am not even good in real numbers
@stefanalecu9532
@stefanalecu9532 Жыл бұрын
Because the world is complex by itself
@enderw88
@enderw88 Жыл бұрын
"Please don't say 90 degrees, we are all adults here"
@vivianriver6450
@vivianriver6450 Жыл бұрын
This one is fun. I actually found your e^(e^x) = 1 video first. I took a different approach to solving this. I tried computing the log-base i of 2, which using log quotient rule, is equivalent to ln(2) / ln(i), the bottom part of which I was able to solve by getting the angle (or family of angles) that has a cosine of 0 and a sine of 1, which is pi/2. Thanks!
@blackpenredpen
@blackpenredpen Жыл бұрын
Awesome, thanks!!
@redroach401
@redroach401 Жыл бұрын
​@@blackpenredpenhello
@simonwillover4175
@simonwillover4175 Жыл бұрын
Of course! In fact, a^b can always = c, for all Complex numbers {a,b,c} where {a,b,c} not = 0 or 1.
@DroughtBee
@DroughtBee Жыл бұрын
I’m scared to look up that proof
@maximilianarold
@maximilianarold Жыл бұрын
@@DroughtBee The proof is left as an exercise for the reader
@TheEGod.
@TheEGod. Жыл бұрын
@@maximilianarold I think there isn't really a proof. I think it's just an assumption. Like 5^3 will always be equal to a value. Lets call this value c. so 5^3 = c. As we know, c = 125, so 5^3 is 125. We knew what a and b were, but we didn't know what c was, but there was an answer. So what if we know the value of a and c, but not b. so i^b = 2. Last time we didn't know a varible, there was an answer, so there must be an answer again. That is my assumption on how he got it, but he might actually have some reason behind it...
@19divide53
@19divide53 Жыл бұрын
Let a^b=exp(b*ln(a)), since exp: C -> C* is surjective, there is a complex number z such that exp(z)=c.
@parikshitkulkarni3551
@parikshitkulkarni3551 Жыл бұрын
I have a truly marvelous demonstration for this proposition which this comment section is too narrow to contain.
@Saytome165
@Saytome165 Жыл бұрын
"Complex number is a pathway to many abilities some consider to be unnatural." - Chancellor Palpatine said during his complex analysis lecture
@srengp3805
@srengp3805 6 ай бұрын
That was the exact line i thought of when first learning about complex numbers
@terryjwood
@terryjwood 2 ай бұрын
He's not wrong.
@chrisjuravich3398
@chrisjuravich3398 Жыл бұрын
Very nice explanation about why the +4n part is needed to complete the answer. i raised to any multiple of 4 will always result in 1.
@beatrix4519
@beatrix4519 11 ай бұрын
this kind of math is so interesting to me I never took precalc or a calculus class just college algebra we only got a slight introduction to imaginary numbers so all of this baffles me glad I don't need calculus for my degree 😅
@tomasgalambos3115
@tomasgalambos3115 Жыл бұрын
I have been watching your videos for about 2 years now, now that Im in UNI, and im learning more and more about math, I can follow the videos much better, and I just love to see the progress, and the interesting things you show here on youtube
@proximitygaming8253
@proximitygaming8253 Жыл бұрын
**For those who want the tl;dr explanation:** i^x = 2, so x = log base i of 2 = ln(2)/ln(i) by base-change. This is just ln(2)/(pi/2 i) = ln(4)/(pi * i).
@mathcat4
@mathcat4 Жыл бұрын
Hey, nice video, I've got a fun challenge for you: Determine all positive integer pairs (p, q) for that p^q + q^p is prime. Not what you usually do, but it has an interesting solution.
@zoomlogo
@zoomlogo Жыл бұрын
oh hello there lol
@Farid_Bang_Official_Channel
@Farid_Bang_Official_Channel Жыл бұрын
Nice question. xD. Since you could say that p is equal to a number 2ⁿ-2 and q is 1 therefore p^q+q^p is 2ⁿ-1. Since i know that it isnt determined whether there is an infinite amount of mersenne or not, answering this question, would be either quite impossible or just impossible. A couple mersenne examples would be (2,1): 3 (4,1) : 5 (6,1) : 7 .... You could generally say, that there are infinitely many tupels where p is a prime -1 and q is 1 so that (p -1)^1 + 1^(p-1) = p So my answer would be that there are infinitely many tuples, as many as there are Prime numbers...
@Farid_Bang_Official_Channel
@Farid_Bang_Official_Channel Жыл бұрын
(2,3)...
@damyankorena
@damyankorena Жыл бұрын
wlog assume p=2 and eval mod3 Very easy ngl
@mathcat4
@mathcat4 Жыл бұрын
@@zoomlogo lmao hi
@SidneiMV
@SidneiMV Жыл бұрын
The "secret" is always the same: put everything in base *e* (Euler's number)
@Player_is_I
@Player_is_I Жыл бұрын
This is my humble request to whomsoever is reading, please consider my problem::: By Euler's identity => e^iπ + 1 = 0 => e^iπ = -1 Square both the sides => (e^iπ)² = (-1)² => e^2iπ = 1 take natural log of both the sides => ln(e^2iπ) = ln(1) => 2iπ = 0 Please explain😢😢😢 By the way I have a couple more such demonstrations that kinda contradicts the identity which I am unable to recall rn, although I also have worked with this a lot, it feels not a peaceful identity at somepoints, But I do remember that the problem in the eq comes right after squaring both the sides. I am not sure with all this as I did this a long time ago but whatever I wrote is what I remember rn, sorry if I wasted any time, please consider atleast replying 🙏🙏🙏
@ianzhou3998
@ianzhou3998 Жыл бұрын
Here is what you wrote: Square both the sides => (e^iπ)² = (-1)² => e^2iπ = 1 ^^This is not true. For complex inputs, a^b^c is not always equal to a^(bc). The rule of complex analysis dealing with log and exponent branches says so. Or else, one can prove anything we want. Here's one of my personal favorites with this fallacy: Suppose we have a real number a. Then, a = e^(ln a) by definition. It follows that, a = e^(1 * ln a) = e^[(2iπ/2iπ)*(ln a)] = e^[(2iπ)*(ln a/(2iπ))]. Applying our fallacy, we see that the above expression equals [e^(2iπ)]^[ln a/(2iπ)]. But e^(2iπ) = 1 by Euler's identity. Thus, we get: a = 1^[ln(a)/(2iπ)]. But 1^x = 1, (unless you use the same fallacy!) so all a = 1. Thus, all real numbers are 1 (obviously not true). BPRP actually did a video on this a while back, seeing if 1^x = 2 is possible. Long story short, that equation had no solutions. But, there was a solution to the equation 1 = 2^(1/x). Raising both sides to the power of (1/x) caused some issues with domain and range restrictions, so the solutions obtained were technically "extraneous."
@Player_is_I
@Player_is_I Жыл бұрын
@@ianzhou3998 Thank you very much for correcting me or rather teaching me the actual reason. I just took a look at some articles, I didn't noticed the actual law which was a^b^c = a^(b×c) for these elements should belong to the Real world. Well I was on the right path to find my mistake on my other such demonstrations that had the same mistake, when I said "the problem in the eq comes right after squaring both the sides". Half knowledge is more dangerous than no Knowledge Anyways thank you for explaining that much and telling about the video of 1^x=2 and sorry If I were to be silly. 😊
@rogierownage
@rogierownage 2 ай бұрын
@@ianzhou3998 This is not quite right according to Microsoft Copilot. What goes wrong is that 1 actually has infinite imaginary representations. Following Euler's formula you get 1 = e^(n2iπ). When n=0, this leads to the real representation e^0 which is ofcourse 1. But if you substitute this for 1 in the earlier equation, you get: ln(e^(2iπ)) = ln(e^(n2iπ)) 2iπ = n2iπ Divide by 2iπ on both sides: 1 = n Which makes sense because n is any integer.
@Fillex5000
@Fillex5000 Ай бұрын
I've seen the explanation below and it's not quite right. Power to multiplication rule (a^b)^c = a^(b*c) is always true and the problem here is dependent on the branch of the ln(x). See, ln(x) has multiple branches we can choose from. Similar to how a square root of 4 can theoretically be 2 or -2, we just assume the positive branch when using the symbol √. Many functions in the complex plane have this property. When doing ln(x) in the complex numbers it's best to first express the x in its polar form re^[i(θ+2πn)] and then do the logarighm. Then you see that (e.g. in an equation) there can be multiple solutions from different branches depending on the n you choose (keep in mind that n has to be an integer).
@narfharder
@narfharder Жыл бұрын
5:09 "Check this out" watch the word "note" at 144p, trippy.
@gietie1694
@gietie1694 Жыл бұрын
you could also take the ilog of 2 and rewrite it as ln(2) / ln(i) = ln(2) / 0.5ln(-1) = 2ln(2) / pi i if im not mistaken
@bijipeter1471
@bijipeter1471 10 ай бұрын
Thank you, sir
@narayanchauhan7541
@narayanchauhan7541 Жыл бұрын
Just asking how did you become so good in maths? I saw your previous videos for doubts and you make questions easy.
@1tubax
@1tubax Жыл бұрын
Practice solving problems, read college textbooks, participate in competitions, watch and learn proofs. Over a few years you'll rack up so much intuition and knowledge if you practice right snd consistently.
@JB-ym4up
@JB-ym4up Жыл бұрын
I took log base i on both sides and got x=logi(2)
@tanvec
@tanvec Жыл бұрын
Please don't say 90 degrees, as we are all adults now...I think I laughed a little more than I should have lol
@blackpenredpen
@blackpenredpen Жыл бұрын
😆
@stephaneclerc667
@stephaneclerc667 Жыл бұрын
I just discovered your channel and it IS GREAT! Your enthusiasm is amazing, I had a math texher like that 25 years ago, you really remind him. (his name was Gustave😂) I'm 38, love maths and I stopped at this level (high school math option in my country) But because of life and the obstacles on the way, I never was able to pursue in polytechnic. But I always kept a close link with mathematics and especially analysis. I litteraly do integrals during my free time, it's so beautiful.. My favorite is to trick arrogant people in the STEM fields with a "simple ∫ 1/(x^4 + 1) dx Most people fall in the trap. Anyway, I love your content and I'm gonna be watching a lot of it to stay sharp! Thank you
@blackpenredpen
@blackpenredpen Жыл бұрын
Thank you very much!!
@DPME820
@DPME820 Жыл бұрын
What trap?
@stephaneclerc667
@stephaneclerc667 Жыл бұрын
@@DPME820 people think it's an Ln
@vowing
@vowing 11 ай бұрын
4:17 me too dawg glad we got one thing in common 💯
@math4547
@math4547 Жыл бұрын
Very nice video wow I'm a really huge math fan and keep it up !
@blackpenredpen
@blackpenredpen Жыл бұрын
Thank you!
@donaldmcronald2331
@donaldmcronald2331 Жыл бұрын
I'd add a simplification. You can pull the 2 inside the ln as an exponent, so 2*ln(2) = ln(2^2) = ln(4). It makes the result a little prettier :D
@govcorpwatch
@govcorpwatch Жыл бұрын
Make π τ again.
@abhirupkundu2778
@abhirupkundu2778 7 ай бұрын
and using ln(a^b)= blna, u can take the minus sign inside to make it ln(4^-1)= ln(1/4), to make it look even prettier
@MikeyBarca02
@MikeyBarca02 Жыл бұрын
I'm so prone to clickbait thumbnails when it comes to maths, usually they don't work on me but your thumbnails always get me😂
@eitancahlon
@eitancahlon Жыл бұрын
please upload more, I really enjoy your videos
@jaypeebeats141
@jaypeebeats141 Жыл бұрын
4:17 "i dont like to be on the bottom, i like to be on the top" xddd
@Tetraverse
@Tetraverse 4 ай бұрын
does he know
@Qbe_Root
@Qbe_Root 2 ай бұрын
As x increases, i^x rotates around the origin in the complex plane. So you just have to make x increase fast enough, and the centrifugal force will stretch the unit circle out to the point that i^x = 2
@gheffz
@gheffz Жыл бұрын
Great video... much appreciated. Your info shared and your style... and your nice manner.
@AbdulBasitWani.
@AbdulBasitWani. Жыл бұрын
You are the best ❤
@بشاررمضان-ع2ت
@بشاررمضان-ع2ت Жыл бұрын
You are great teacher
@hayn10
@hayn10 Жыл бұрын
4:17 🤨 4:18
@jesusnoagervasini8207
@jesusnoagervasini8207 Жыл бұрын
The answer is obviously log(i)2
@awoomywang
@awoomywang Жыл бұрын
HI STEVE, CAN I GET A PROMO CODE FOR YOUR LAMBERT W FUNCTION PURPLE TSHIRT BECAUSE I WANT TO ORDER 100 OF IT AND THE SHIPPING PRICE IS 800 DOLLARS
@seanwang6716
@seanwang6716 Жыл бұрын
Yes so true
@seanwang2635
@seanwang2635 Жыл бұрын
i agree, the lambert w function shirt looks so good haha
@spoojy7881
@spoojy7881 Жыл бұрын
bprp merch ftw
@pooface432
@pooface432 Жыл бұрын
makes you feel smart
@blackpenredpen
@blackpenredpen Жыл бұрын
Could you send me an email blackpenredpen@gmail.com and let me know why you are ordering 100 t-shirts? I will see what I can do for you.
@dm319-j5y
@dm319-j5y 3 ай бұрын
I just checked this on a 42 year old HP-15c, and I'm super impressed it got -2.
@Giannhs_Kwnstantellos
@Giannhs_Kwnstantellos Жыл бұрын
x= log i (2), taylor series, easy
@aguyontheinternet8436
@aguyontheinternet8436 Жыл бұрын
Before watching video i^x = 2 x=log_{i}(2) x=ln(2)/ln(i) ln(i)=iπ(1+2n)/2 for any integer n x=(2ln(2))/(iπ(1+2n)) x=(-2 i ln(2) )/( π (1 + 2n) ) focusing on the principle value, we have -2i ln(2) / π Edit: shoot I didn't notice the extra answers with raising i to the fourth power
@beginneratstuff
@beginneratstuff Жыл бұрын
I did it this way too before watching the vid lol I also didn't notice the extra answers, also I think you made a slight mistake, ln(i) = iπ(1 + 4n)/2 after you combine the π/2 with the 2πn into a single fraction and factor out the π. It didn't affect the principal answer tho
@JonnyMath
@JonnyMath Жыл бұрын
Your videos are amazing, thanks professor!!! 🤗🤩🥳
@st3althyone
@st3althyone Жыл бұрын
Yes, it can. Take the natural log of both sides to get the exponent out, then divide by the ln i. X=ln 2 / ln i.
@jessejordache1869
@jessejordache1869 Жыл бұрын
The term in the denominator is sort of kicking the problem back at you. 'e^x = i' is not at all clear to me.
@hoteny
@hoteny Жыл бұрын
0:57 why do you guys hate 90 degrees and it always has to be pi over whatever?
@stratonikisporcia8630
@stratonikisporcia8630 Жыл бұрын
Degrees are arbitrary, radians give the arc length
@puremage0
@puremage0 4 ай бұрын
​@@stratonikisporcia8630every measuring unit like metres, kilogram, seconds, ampere, volts are all made up for convinience.
@rokaq5163
@rokaq5163 3 ай бұрын
Radians are much more convenient mathematically, albeit less intuitive than degrees. If you go for function over form, radians are the way to go. And math is basically all function and zero form, so there's that.
@gswcooper7162
@gswcooper7162 Жыл бұрын
I would love to see you go further than complex numbers and solve an equation with quaternions instead - maybe something like x^x = 2?
@Cubowave
@Cubowave Жыл бұрын
(4×ln2)/2πi is also a solution
@Ноунеймбезгалочки-м7ч
@Ноунеймбезгалочки-м7ч 11 ай бұрын
i^x=(-1^0.5)^x=-1^x/2, and you can only get -1 & 1 out of powers of -1, should be impossible if I got it right
@mm0691
@mm0691 4 ай бұрын
Is that mean we would need to have a integer m & n to show every situation of the solution, where the n comes from the angle (2 pi n) and the m comes from i^4 ? ( i^(4m) ) That is A LOT of solutions
@روائعالقرآن-ز1ن
@روائعالقرآن-ز1ن Жыл бұрын
Can you do a video on how to change the pens in your hand? Thanks for your wonderful videos
@_adityaacharya_8550
@_adityaacharya_8550 Жыл бұрын
we can use ln(z)= ln(|z|) + i(2npi+theta) too
@Red-Brick-Dream
@Red-Brick-Dream Жыл бұрын
"We are adults now, so say 'pi over 2.'" Thank you for this. From the bottom of my tired heart.
@fizixx
@fizixx Жыл бұрын
i^i. . . . .my favorite Very kewl video....love the info
@hk4587
@hk4587 Жыл бұрын
Please make a video on how to solve any kind of ∑ problem... I need to learn..
@zetadoop8910
@zetadoop8910 Жыл бұрын
its a pleasure watching you. thanks
@mathmachine4266
@mathmachine4266 2 ай бұрын
ln(2)/ln(i) = ln(2)/(πi/2) = -2ln(2)i/π i^(-2ln(2)i/π)=2 Although, actually, the numerator can be ANY natural logarithm of 2 (ln(2)+2πNi)/ln(i), where N is any integer So i^(4N-2ln(2)i/π) = 2 That should hopefully make sense, since i^4=1, whatever power you raise i to, you could also add or subtract any multiple of 4. x = 4N-2ln(2)i/π, where N is any integer
@its_eoraptor99
@its_eoraptor99 Жыл бұрын
Bro you look so much better without a beard, no kidding
@gmjackson1456
@gmjackson1456 Жыл бұрын
Great job!
@wolfelkan8183
@wolfelkan8183 Жыл бұрын
Request: is there a complex number x such that 2^x = x?
@gamerpedia1535
@gamerpedia1535 Жыл бұрын
2^x = x e^(x ln 2) = x x e^(-x ln 2) = 1 -x ln 2 = W(-ln 2) x = W(-ln 2) / -ln 2 Now there's a couple cool things of note here. Any number such that n = W(-ln x) / -ln x can be represented as an infinite power tower. I'll post the proof in a separate reply underneath this one. The other cool thing is that for 2^x = x, you can do 2^(2^x) = x or 2^2^x and following the chain, you're solving for the infinite power tower of twos
@gamerpedia1535
@gamerpedia1535 Жыл бұрын
n^x = x xln(n) = ln(x) ln(n) = ln(x)e^(-ln(x)) W(-ln(n)) = -ln(x) e^(-W(-ln(n))) = x Identities of the W Lambert function tells us now that x = W(-ln(n))/-ln(n) For n^x = x So that's pretty cool, it's a shortcut to solve any convergent power towers.
@coolcapybara111
@coolcapybara111 Жыл бұрын
Broo this is insaneee 😵
@michaelbaum6796
@michaelbaum6796 Жыл бұрын
Great, that is fascinating 👍
@digitalfroot
@digitalfroot Жыл бұрын
this was such a fun video lol i love how happy you get
@SAGEmania-q8s
@SAGEmania-q8s 11 ай бұрын
lovely. Thank you. I will visit here whenever I got freetime like now.
@anestismoutafidis529
@anestismoutafidis529 Жыл бұрын
In case of the derivation of y= i^x to y´=x*i if x=2: i^2(Y)= 2(y´)
@Cosmomaths
@Cosmomaths 2 ай бұрын
Respect, i wish i’ll have you as math teacher when i’ll go to college 😂
@jaii5955
@jaii5955 Жыл бұрын
Our genius is back we amazing questions 😀
@1224chrisng
@1224chrisng Жыл бұрын
my man's hoarding whiteboard markers like they're Hagaromo chalk
@blackpenredpen
@blackpenredpen Жыл бұрын
😂
@sardine_man
@sardine_man 7 ай бұрын
I got the same answer as wolfram alpha by simply thinking that x=a+bi and then from there rewrite i^x as e^(pi/2*i(a+bi)) and then distribute and match the e^(pi/2*a*i) part to match the angle 0+2pi*n and then I matched the e^(-pi/2*b)=2 so in that way you match 2 written in the form r*e^xi, 2=2*e^(2pi*n)
@PennyLapin
@PennyLapin Жыл бұрын
Is there a use to solving this for the more general form of e^i(pi/2+2npi) and show that you can produce an x that satisfies all infinitely many integer values of n? I looked at that expression and rewrote the theta value as (pi+4npi)/2 to make it more comfortable, then I set (e^i(pi+4npi)/2)^x = 2 and followed the same process to isolate the x from the equation. (e^i(pi+4npi)/2)^x = 2, n ∈ Z x * i(pi+4npi)/2 = ln(2) x = 2ln(2)/i(pi+4npi) x = -2iln(2)/(pi+4npi) Someone could ask "but what if we don't start with e^i(pi/2)? What if we start with e^i(5pi/2), or e^i(13pi/2)?" I asked that while watching, but I realized that other polar values of i can still be raised to a power that makes i^x = 2. Edit: Thanks to another discussion I thought about possible problems here and the reason why the video's focus on the principal value was there, based on where ln(x) isn't well-defined. If anyone has input on where this does and doesn't work, that would be appreciated!
@neoxus30
@neoxus30 Жыл бұрын
If you wanna make it work for non-positive complex numbers, just change the 4npi part. The solution of i^x = -2 is 2n - 2iln(2)/π
@bettyswunghole3310
@bettyswunghole3310 Жыл бұрын
I shudder to think of the complexity of any maths problem that would require the use of a green pen in addition to the red, black and blue!😄
@armanavagyan1876
@armanavagyan1876 Жыл бұрын
Stunning proof👍👍👍
@lawrencelawsen6824
@lawrencelawsen6824 21 күн бұрын
I love this channel
@spoon_s3
@spoon_s3 Жыл бұрын
i^x = 2 x = ln(2)/ln(i) x = ln(2)/(i*(pi/2 + 2n*pi)) x = -iln(2)/(pi/2 + 2n*pi) Where n is all integers (arguably) more simple solution
@carlopaternoster5878
@carlopaternoster5878 Жыл бұрын
I tought the same, but it seems this is not the same as what is in the video. I do not know how to pass form one to another, they should be the same
@ClukrFG
@ClukrFG Жыл бұрын
BPRP: x=4n-(2iln2)/π My mindset: x=log_i(2)
@randomboi550
@randomboi550 4 ай бұрын
this is the first time I attempted the question on the thumbnail and actually got the answer before watching the video. I was excited at first but now I realise that this may be the beginning of me not needing to watch his videos to get my mind blown, which is pretty sad. I loved the mystery and the elegance of the solution, it would only blow my mind if I couldn't figure it out myself or needed a lot of hints. But now that I can do this myself, the magic of math is gone. Now I'm just sad.
@kaisson8
@kaisson8 Жыл бұрын
I didn't get why we have to write i^4n ? thank you !
@scottleung9587
@scottleung9587 Жыл бұрын
I got the principal value for x just fine, but for the general solution I somehow ended up with 4n in the denominator.
@darrenxavierjohan861
@darrenxavierjohan861 Жыл бұрын
Same :(
@ezio99ez
@ezio99ez Жыл бұрын
Can you have exact result for x, in x^i = i^x ?
@japanpanda2179
@japanpanda2179 Жыл бұрын
Yes. x is either i or -i. Sorry if this is disappointing.
@Yaash-ph1pi
@Yaash-ph1pi Жыл бұрын
Can u do a video where to use blackpen and redpen
@jmlfa
@jmlfa 4 ай бұрын
The rule (a^b)^c = a^bc … IS NOT VALID FOR IMAGINARY NUMBERS. If it were, then it is easy to show that -1 = 1: Simply replace 1 by e^(2pi*i) in the right part of the equation 1 = sqrt(1).
@donovanknutson5128
@donovanknutson5128 Жыл бұрын
-iLn(2)/pi
@Harrykesh630
@Harrykesh630 Жыл бұрын
Professor please make a video on tricks used to solve limits
@MC_Transport
@MC_Transport Жыл бұрын
Can you do 100 related rates please
@xinpingdonohoe3978
@xinpingdonohoe3978 Жыл бұрын
Consider a≠0≠b as complex numbers. Then a^x=b can be solved. Such is the power of the complex plane. And then, if one of a or b is equal to 0, the other must be as well in order to be solved.
@simonwillover4175
@simonwillover4175 Жыл бұрын
Or a = 0 and b = 1, then x = 0, since 0^0 is (typically) defined as being 1.
@xinpingdonohoe3978
@xinpingdonohoe3978 Жыл бұрын
@@simonwillover4175 yes, if that computational convention is followed, then that is the exception.
@souvikroy3584
@souvikroy3584 Жыл бұрын
I have known a lot about complex from your video ✨
@multilingualprogrammer3154
@multilingualprogrammer3154 Жыл бұрын
@Blackpenredpen , look up this book called " (Almost) impossible integrals, sums, and series" and do a video on it.
@lucidx9443
@lucidx9443 Жыл бұрын
Nice. Can you please also cover possible applications? I find it easier to remember that way!
@esajpsasipes2822
@esajpsasipes2822 Жыл бұрын
One application is to exercise your math skills...
@lucidx9443
@lucidx9443 Жыл бұрын
@@esajpsasipes2822 That's given right he's an effective communicator. I'm just asking for actual applications.
@esajpsasipes2822
@esajpsasipes2822 Жыл бұрын
@@lucidx9443 I was more wanting to say that there might not be any (not sure), but even if there aren't any direct applications, it at least serves as an exercise (or entertainment i guess).
@ryanjackson0x
@ryanjackson0x Жыл бұрын
More generally, quantum mechanics uses this type of math
@prg_prashant
@prg_prashant Жыл бұрын
Sir, what's about taking log both sides...
@jimnewton4534
@jimnewton4534 Жыл бұрын
It is not clear to me that (x^y)^i = x^(iy). Clearly such is true if you look at an integer exponent, but it is NOT TRUE for general exponents. For a counter example consider f(t)=e^(i π t), which is clearly not identical to 1. However consider for x>0, f(x) = e^(i π 2t/2) = (e^(iπ))^2^(t/2) = ((-1)^2)^(t/2) = 1^(-t/2) = 1. This shows that sometimes it is false that x^(yz) = (x^y)^z.
@19divide53
@19divide53 Жыл бұрын
It should be exp(z)^w=exp((z+2kπi)w), but general exponents a^z is defined by a^z=exp(z*ln(a)). In the video bprp is considering only the principal branch so it simplifies to exp(zw)=exp(z)^w.
@ガアラ-h3h
@ガアラ-h3h Жыл бұрын
My take i^p = 2 => ln 2 = p*ln i => = ln 2 *2 = p * ln -1 => ln2 * 2 = p * ipi => p = ln2 *2/ipi which can be written as -ln 2 * 2i/pi what a beautiful result
@dataweaver
@dataweaver Жыл бұрын
i^x=2 is the same as e^(½πix)=e^(ln2). So x=ln2⁄(½πi), or −i⋅ln4∕π
@AC-zv3fx
@AC-zv3fx 11 ай бұрын
I got everything but why on 5:54 we don't multiply everything on the right side by 4 instead😅
@Ramp4ge28
@Ramp4ge28 7 ай бұрын
Complex numbers are like cheating, you can have everything with they
@kiza_l1247
@kiza_l1247 Жыл бұрын
can u do vid solve equation erf(x) = 2 find x?
@olahalyn4139
@olahalyn4139 Жыл бұрын
I wrote the answer as ln((2)^(2)(-i/pi)). I wonder if the whether general answer of i^x = a, would always be ln((a)^(a)(-i/pi)). It looks quite nice as well.
@MyNameIssaSimon
@MyNameIssaSimon Жыл бұрын
Try an induction proof
@olahalyn4139
@olahalyn4139 Жыл бұрын
Tried it lol. Doesn't work. I did find after starting again that the actual general form is x = ln(a^(-2i/pi)) which I could prove by induction. Thanks for the hint. @Simon N I don't get to do maths much these days as I have left sixth form and uni course doesn't have any advanced maths in it really alway fun when bprp uploads.
@person1082
@person1082 Жыл бұрын
just take log_i of both sides
@amrz1990
@amrz1990 Жыл бұрын
Why wolfpharm alfa give the answer with log not ln ?
@VSP4591
@VSP4591 Жыл бұрын
Splendid.
@varun3282
@varun3282 Жыл бұрын
yep solved x=(2/i*2n+1*pie)ln2 n belongs to Integers.
@MathsKaDar
@MathsKaDar Жыл бұрын
Is there is any solution for √x+1=0 I wanna know how u gonna solve it
@stratonikisporcia8630
@stratonikisporcia8630 Жыл бұрын
√x + 1 = 0 √x = -1 By definition, i² = -1, hence: x = i or x = -i
@Andy-ju8bb
@Andy-ju8bb Жыл бұрын
Is there a particular reason for writing 2ln2 in the solution rather than ln4? I assume since that's the answer on WA, there must be a reason.
@Engy_Wuck
@Engy_Wuck Жыл бұрын
it's the standard form, because it's "more beautiful" to have the lowest possible number in the ln. Otherwise you could also write "ln 4^i"
@Andy-ju8bb
@Andy-ju8bb Жыл бұрын
@@Engy_Wuck Thank you.
@General12th
@General12th Жыл бұрын
Hi Dr. Pen!
@raghavdhyani5739
@raghavdhyani5739 Жыл бұрын
brother i took both side to the power i then replaced i^i by e^-pi/2 then after something i got x = i^-4lni/pi pls explain how much wrong i am
@Toxic__rl
@Toxic__rl Жыл бұрын
Hey, so i had an exam today, and 'this woman o_o' gave us a quiz online, everyone could get different thing to solve... I got to do an integral of x^100 * sinx dx... I've looked at it and was like "wtf...". Is there any 'clever' way to solve this or my only choice was doing integrating by parts / D I method (not all the way ofc o_o... I've made 5-6 multiplications and then + ... + C xD)
@Toxic__rl
@Toxic__rl Жыл бұрын
@blackpenredpen HELP (if it's even possible) XD
@ANTI_UTTP_FOR_REAL
@ANTI_UTTP_FOR_REAL Жыл бұрын
At school Teacher: Whats your favorite number? A random kid: 3 Another kid: 7 This guy: *i*
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