combining rational exponents, but using calculus,

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  • เผยแพร่เมื่อ 30 ก.ย. 2024

ความคิดเห็น • 331

  • @blackpenredpen
    @blackpenredpen  10 หลายเดือนก่อน +36

    Learn more calculus on Brilliant: 👉brilliant.org/blackpenredpen/ (now with a 30-day free trial plus 20% off with this link!)

    • @duckimonke
      @duckimonke 10 หลายเดือนก่อน +3

      first + second like!

    • @xflr-6659
      @xflr-6659 10 หลายเดือนก่อน +1

      Day 2 of asking BPRP to do another video with our best friend and sells new t-shirt of it

    • @duckimonke
      @duckimonke 10 หลายเดือนก่อน +1

      [repost] BTW, you should try this equation I came up with! It's a bit challenging.
      i^x=e^x^i
      Solve for all values of x.

    • @whittydabomb2496
      @whittydabomb2496 10 หลายเดือนก่อน

      Talk about googology or even make a series on it, its very cool

    • @people3.14
      @people3.14 10 หลายเดือนก่อน

      I have a question. First, I am Korean, so I might not be well in English.
      I learned some ideas.
      : a^4 = a×a×a×a, so a^4 = a^3 × a^1 = a^(3+1)
      Therefore, if we want to solve, we can follow this way
      : e^1/2 * e1/3 = e^(1/2 + 1/3) = e^5/6
      I think it is easy than that way.
      But, I think also It.
      : Inspite of the fact that you have already known this way, the core of this video is "Using calculus".
      Thank you. I am waiting for your call..? Response..? Anyway, please tell me what you wanted to say.
      + I am really love all of you. Lol😂

  • @smabdullahaljobairraihan
    @smabdullahaljobairraihan 10 หลายเดือนก่อน +809

    Seems like a hard way of proving 1+1=2

    • @bahaagamer9500
      @bahaagamer9500 10 หลายเดือนก่อน

      There actually is a 374 page proof for 1+1=2

    • @OrdinarySonicfanMmKay
      @OrdinarySonicfanMmKay 10 หลายเดือนก่อน +7

      exactly

    • @bachoundaseddik250
      @bachoundaseddik250 10 หลายเดือนก่อน +4

      you wouldnt get it

    • @tsawy6
      @tsawy6 10 หลายเดือนก่อน +2

      Is illustrative

    • @anuragguptamr.i.i.t.2329
      @anuragguptamr.i.i.t.2329 10 หลายเดือนก่อน +60

      No dude. Proving 1+1=2 is a much much more difficult task than that. 1+1=2 is a 180 pages long published proof. 😅

  • @Ninja20704
    @Ninja20704 10 หลายเดือนก่อน +460

    A lot of people seem to be missing the point.
    The point here is justifying that we can even add the powers in the first place. Because like what he showed in the first example, the usual way we prove x^a*x^b= x^(a+b) is only valid when a and b are positive integers. So if the powers are not positive integers, we need a another way to justify that we can still add the powers.

    • @Lolwutdesu9000
      @Lolwutdesu9000 10 หลายเดือนก่อน +25

      Er, no? It's valid for real numbers, not just integers. It's a basic idea taught at high school when exponent laws are introduced. Where are you getting your ridiculous idea from?

    • @Ninja20704
      @Ninja20704 10 หลายเดือนก่อน +122

      @@Lolwutdesu9000 I am very aware that it is true for all reals. I at no point said that the rule doesn’t hold outside of positive integer powers. I’m talking about the way we prove it.
      The usual way that we prove x^a*x^b=x^(a+b) is by saying
      x^a*x^b=(x*x*x…*x)*(x*x*x…*x) (a x’s in the first bracket, b x’s in the second)
      = x*x*x…*x (a+b x’s)
      =x^(a+b).
      (What he did with the specific example of e^2*e^3)
      But the proof only shows that it works if a and b are positive integers. How can we immediately say that the rule holds if a and b were negative, fractions, irrationals, etc? Clearly, we need another way to justify it.
      What he did in the video was show that we can still add the powers even if they are not positive integers.
      I highly suggest you read carefully people’s comments before replying.

    • @SunnyKumar-gk7fr
      @SunnyKumar-gk7fr 10 หลายเดือนก่อน +18

      ​@@Ninja20704let k = e^(1/6)
      therefore, the expression becomes (k^3)×(k^2)
      =k^5
      =e^(5/6)
      isn't this just an easier way of proving this?

    • @Ninja20704
      @Ninja20704 10 หลายเดือนก่อน +37

      @@SunnyKumar-gk7fr the exponent rule (x^m)^n=x^mn (which is how you get e^(1/2)=e^(3/6)=[e^(1/6)]^3=k^3) requires knowing power addition rule first so it is back to the same question of proving the addition rule works for fractional powers.

    • @guyonYTube
      @guyonYTube 10 หลายเดือนก่อน

      im actually curious; how does the exponent rule (x^m)^n = x^mn require the power addition rule first to be proved? how is it even proved?@@Ninja20704

  • @vonneumann6161
    @vonneumann6161 10 หลายเดือนก่อน +289

    Doesn’t the proof of e^x expansion already assume x^a*x^b = x^(a+b)?

    • @fahrenheit2101
      @fahrenheit2101 10 หลายเดือนก่อน +98

      The e^x expansion is often taken as a definition instead. A definition that encapsulates what is meant by raising to non integer powers.
      To prove it some other way, you first need to even define what it means.

    • @vonneumann6161
      @vonneumann6161 10 หลายเดือนก่อน +18

      @@fahrenheit2101 Oh that’s true. So in this case e is defined as e^1?

    • @fahrenheit2101
      @fahrenheit2101 10 หลายเดือนก่อน +3

      @@vonneumann6161 yes i believe so.

    • @vonneumann6161
      @vonneumann6161 10 หลายเดือนก่อน

      @@fahrenheit2101 thanks

    • @mohamedibrahim1023
      @mohamedibrahim1023 10 หลายเดือนก่อน +11

      No it doesn’t assume this , as the maclaurin series expansions is given from the nth derivative of a function , so the expansion is really the definition that you can manipulate to get identities ,, a fun fact from this definition we need to define 0^0 in this case to be 1

  • @physicsfaith
    @physicsfaith 10 หลายเดือนก่อน +62

    Wow, that’s beautiful man. I’m surprised a lot of people are missing the point. We often bring in unproven assumptions that are correct, and so we use them. But sooner or later we need to prove that we can use the simpler tricks… great use of power series, combinatorics, binomial theorem…

    • @AT-zr9tv
      @AT-zr9tv 10 หลายเดือนก่อน +1

      It would probably have been clearer had he stated the problem as let's prove that e^x * e^y = e^(x+y) for x and y real numbers. Having x=1/2 and y=1/3 just clutters things unnecessarily.

  • @JacqueyQuacky
    @JacqueyQuacky 10 หลายเดือนก่อน +29

    I literally just had a tutorial where we had to rigorously prove exp(x+y)=exp(x)exp(y) with taylor/series expansion as a method. thank you:)

    • @blackpenredpen
      @blackpenredpen  10 หลายเดือนก่อน +13

      I actually did that originally but I thought it would be more friendly to do it with 1/2 and 1/3. Btw the original video is in the description if you are interested.

  • @donwald3436
    @donwald3436 10 หลายเดือนก่อน +5

    How is it possible for a 16 year old to be a calculus teacher for 10 years?

  • @elektronikvideos-bremen2873
    @elektronikvideos-bremen2873 10 หลายเดือนก่อน +24

    Although I'm out of school for more than 20 years I still enjoy such mathematical juggling.
    Thanks a lot!

  • @BlueGolden-xq5su
    @BlueGolden-xq5su 10 หลายเดือนก่อน +12

    When the blue pen joins the fight, you know it’s a pretty hard question

  • @RickyWallace
    @RickyWallace 10 หลายเดือนก่อน +11

    This was fun! Seeing it come together was beautiful, and your cheery style of “bringing them to the party” and “what do?” made me laugh. Been watching for years and haven’t commented yet, so hello Steve! Thanks for the edu-tainment!

  • @erggish
    @erggish 10 หลายเดือนก่อน +2

    exp(1/2) exp(1/3)
    exp(3/6) exp(2/6)
    now you can write it as multiplication of exp(1/6) (or sixth-roots of e) terms to get 5 of them. Over...

  • @sergeygaevoy6422
    @sergeygaevoy6422 10 หลายเดือนก่อน +5

    This approach allows us to define exp(almost everything), for example of a matrix, an octonion.
    And if the a*b = b*a then exp(a + b) = exp(a) * exp(b) = exp(b) * exp(a) for the matrices a and b.
    For octonions it is a litttle bit confusing: we do not have associativity.

  • @ManishaSingh-mb7lv
    @ManishaSingh-mb7lv 10 หลายเดือนก่อน +1

    Hey Steve Sir I am Pratik a school student and a calculus Geek . I have a challenge for you Solve The Couchy Integral whose explanation can be understood by a calculus 1 student

  • @sleeplessdistrict3897
    @sleeplessdistrict3897 8 หลายเดือนก่อน +3

    “Bro I swear my methods easier”
    Bros method:

  • @bariumselenided5152
    @bariumselenided5152 10 หลายเดือนก่อน +4

    I clicked on this knowing that the title was too simple, and there'd be some fun maths ahead. Wasn't disappointed

  • @jim2376
    @jim2376 9 หลายเดือนก่อน +1

    Hint: 1/2 + 1/3 is the same as 3/6 + 2/6. Both equal 5/6. Calculus? I'm going with the KISS principle. e^(5/6)

  • @nishiharae
    @nishiharae 10 หลายเดือนก่อน +16

    1/2=3/6, 1/3=2/6.
    3/6+2/6=5/6
    seems like a complicated way of adding 2 fractions no?

    • @Ninja20704
      @Ninja20704 10 หลายเดือนก่อน +11

      That was not at all the point. The point was that how do we know we can add the powers when the usual way we prove x^a*x^b=x^(a+b) is only valid when a and b are positive integers.

    • @HalobeatWatcher
      @HalobeatWatcher 10 หลายเดือนก่อน +4

      I must admit. Yes, it is too complicated, but to be honest.
      Can you prove: a^b.a^c = a^(b+c), when a,b,c are real numbers. Ye, it is easily proven with a,b,c are integers, but what about non-integers? Can you prove that? Of course you can, but proving that will be much harder than proving e^(1/2).e^(1/3) = e^(5/6)
      Nowdays, we use the exponent rule without knowing where it come from. If you think this is unesscesary complicated, that's absolutely okay, because mathematicians are really ridiculously rigorous, even proving 1+1=2 using abstract algebra is unescessary complicated :P. In conclusion, mathmaticians are that one friend when got bored lol

  • @rogerkearns8094
    @rogerkearns8094 10 หลายเดือนก่อน +39

    Just call it sixth root cubed, times sixth root squared, and add the 2 and 3 just as in the first example.

    • @buycraft911miner2
      @buycraft911miner2 10 หลายเดือนก่อน +2

      Then you have to prove the same thing, but written differently

    • @rogerkearns8094
      @rogerkearns8094 10 หลายเดือนก่อน +5

      @@buycraft911miner2
      Well, just write down sixth root of e five times, similar to how he treated e the first time.

    • @buycraft911miner2
      @buycraft911miner2 10 หลายเดือนก่อน +14

      @@rogerkearns8094 the point of the video is to prove e^a*e^b = e^(a+b) for all real numbers, and therefore also prove that (e^a)^b = e^(ab), which is derived from the last property.
      By saying sqrt (e) * sqrt 3(e) = (sqrt 6(e))^5 = sqrt 6(e^5), you are assuming (e^1/6)^5 = e^(1/6*5) for non integers, which we have yet to prove.

    • @rogerkearns8094
      @rogerkearns8094 10 หลายเดือนก่อน +1

      @@buycraft911miner2
      Oh, ok. Cheers, then :)

    • @oenrn
      @oenrn 10 หลายเดือนก่อน +1

      ​@@buycraft911miner2I don't think sqrt means what you think it means.

  • @Inspirator_AG112
    @Inspirator_AG112 10 หลายเดือนก่อน +1

    *@[**03:04**]:*
    Infinitely large polynomial multiplication table.

  • @thijsminnee7549
    @thijsminnee7549 10 หลายเดือนก่อน +1

    Nice proof, now I know how to proof that e^a×e^b=e^(a+b) too.

  • @paltze
    @paltze 10 หลายเดือนก่อน +3

    That's the most badass way possible for reminding us of power series

    • @stevenfallinge7149
      @stevenfallinge7149 10 หลายเดือนก่อน

      Typically exp is defined as a power series and then you prove exp(a+b)=exp(a)exp(b) exactly this way because it's most straightforward this way (after proving some preliminary things about convergence of series).

  • @actualRocketScientist
    @actualRocketScientist 10 หลายเดือนก่อน +1

    That's pretty cool but seems unnecessary. If you raise both sides by come denominator of 6 then you can just add as normal and then take the sixth root it should give me the same result

  • @duckimonke
    @duckimonke 10 หลายเดือนก่อน +2

    BTW, you should try this equation I came up with! It's a bit challenging!
    i^x=e^x^i
    Solve for all values of x.

  • @SylComplexDimensional
    @SylComplexDimensional 10 หลายเดือนก่อน +2

    That piano 🎹 ‼️ .. wow Cauchy product & power series analysis of matrix diagonals!

  • @ADITHIYAஆதித்யாஆதித்யாஹரிபாஸ்க

    insted of that why sir can you try summation of limits using and integrate you can get the answer.

  • @iliyansvechev8113
    @iliyansvechev8113 10 หลายเดือนก่อน +4

    e

  • @creativename.
    @creativename. 10 หลายเดือนก่อน +1

    One must imagine sisyphus doing math

  • @nathanjamesanderson4189
    @nathanjamesanderson4189 10 หลายเดือนก่อน +1

    i wish you were my high school math teacher

  • @maniamhungry4896
    @maniamhungry4896 10 หลายเดือนก่อน +2

    one must imagine blackpenredpen happy

  • @hotlatte1222
    @hotlatte1222 10 หลายเดือนก่อน +1

    Well. We also know e^i thita = cos thita +isin thita. So please try again with (cos 1/2i + isin 1/2i)•(cos 1/3i + isin 1/3i)

  • @cosmicnomad8575
    @cosmicnomad8575 10 หลายเดือนก่อน +8

    This channel never disappoints

  • @richardtrager7125
    @richardtrager7125 10 หลายเดือนก่อน

    I was actually thinking about the problem at 14:44 and didn’t realize the sum of the rows equals to the sum of the columns. I felt so stupid trying to compute each shape’s value 💀💀💀

  • @ShaunakDesaiPiano
    @ShaunakDesaiPiano 10 หลายเดือนก่อน

    And of course the 1/2 and 1/3 are nothing special. You can generalise method to any non-integer rational number (though it would also work for integers, it would be overkill) and in fact any real number.
    I was wondering - I don’t see why it wouldn’t work for complex numbers? In which case would it be a way to prove that the laws of indices can be extended to complex numbers without using Euler’s Formula and compound angle trig formulae?

  • @kb27787
    @kb27787 10 หลายเดือนก่อน +11

    Let e^(1/2) = A and e^(1/3) = B; A^2 = e and B^3 = e. Therefore, (AxB)^6 = A^6 x B^6 = (A^2)^3 x (B^3)^2 = e^3 x e^2 which would give you the original question that you admit is equal to e^5... so (AB)^6 = e^5 so AxB = e^(5/6). e^(1/2) x e^(1/3) = e^(5/6)...

    • @lih3391
      @lih3391 10 หลายเดือนก่อน +1

      It dont work for irrational numbers with no denominator

    • @Cloud88Skywalker
      @Cloud88Skywalker 10 หลายเดือนก่อน

      @@lih3391 with continued fractions you get a denominator for the irrationals.

    • @jakobr_
      @jakobr_ 10 หลายเดือนก่อน

      @@lih3391That follows from the continuity of e^x. Once we’ve proven it for the rationals we have it for the reals.

  • @idjles
    @idjles 10 หลายเดือนก่อน +1

    OHHHH! this is going to help me find a new proof of Pythagoras Theorem!!!

  • @TheEternalVortex42
    @TheEternalVortex42 10 หลายเดือนก่อน

    Of course this generalizes easily to show exp(z+w) = exp(z)exp(w) for all complex numbers.

  • @BrickManAnimations
    @BrickManAnimations หลายเดือนก่อน

    I just did 1/2+1/3 in my head which is 5/6 once a common denominator is found.

  • @Unlimit-729
    @Unlimit-729 2 หลายเดือนก่อน

    e^(1/2) * e^(1/3)
    Next step:
    e^(3/6) * e^(2/6)
    Next step:
    e^(5/6)
    Answer:
    e^(5/6)

  • @TexasEngineer
    @TexasEngineer 10 หลายเดือนก่อน

    How come I did in my head in 10 seconds what you took 15 minutes to do. That I will never understand. I never got a memo that adding exponents was limited to integers. Maybe because I worked with a side rules and logarithms in my day. If I was in doubt I could use my calculator to confirm I was correct.

  • @alfredocanizares7158
    @alfredocanizares7158 10 หลายเดือนก่อน

    Marvellous!!! A big hug from Spain!! 🐒

  • @SmokuZnadPotoku
    @SmokuZnadPotoku 3 หลายเดือนก่อน

    0:52 I really love your jokes and your teaching, keep it up bprp :D

  • @rickyng1823
    @rickyng1823 10 หลายเดือนก่อน

    The double summation and rearrangement of the summands require absolute convergence of both series--something that should be well explained first before taking it for granted. A more appropriate proof at the Calculus level, even for irrational powers, is to go through the integral definition of natural logarithm and use inverse.

  • @Lucas-s6y
    @Lucas-s6y 9 หลายเดือนก่อน

    After all the craziness:
    “What’s 1/2 + 1/3, don’t say 2/5”😂

  • @bernaldbread5652
    @bernaldbread5652 10 หลายเดือนก่อน +1

    I LOVE YOU

  • @SteveSiaterlis
    @SteveSiaterlis 7 หลายเดือนก่อน

    2:38 I think that you have to put parenthesis because this is like a sigma inside another sigma you did it next with the same notation. How we understand what you mean? I usually put parenthesis at the start and the end of large operators like sigma, product pi, integral and others..
    Only if there isn't anything else in the expression I don't put parenthesis
    And I think because this variables in large operators are local you can use again k
    7:53 here you put a sigma into a sigma so there isn't a problem and now you have to put another variable because now the sigma inside can use the two variables but another sigma somewhere else can use n because it's a local variable not global.

  • @Apollorion
    @Apollorion 6 หลายเดือนก่อน

    Does that binomial theorem still hold for numbers that do *not* imply that ab=ba ? (e.g. quaternions etc.)

  • @raczburin_p.a
    @raczburin_p.a 10 หลายเดือนก่อน

    1:55 That is not true for x = 0... (Unless, of course, you fallaciously let ‘0⁰ = 1’)

  • @ВикторПоплевко-е2т
    @ВикторПоплевко-е2т 10 หลายเดือนก่อน

    14:42 couldn't you just summed 1/3 and 1/2 and got the answer by the power rule?

  • @zaenalaabdenabdulrahim9076
    @zaenalaabdenabdulrahim9076 10 หลายเดือนก่อน

    e^(5x)+2^x=x!+2x^2 ? anyone now an answer to this equation in the positive range?

  • @janami-dharmam
    @janami-dharmam 9 หลายเดือนก่อน

    But I do not know the proof of the binomial theorem for negative and fractional powers (not to talk about irrational exponents). We never learnt that but we all assumed that is the bible.

  • @jannegrey593
    @jannegrey593 9 หลายเดือนก่อน

    For once I felt smarter because I knew the answer in like 5 seconds. But I couldn't tech it like you.

  • @romain.guillaume
    @romain.guillaume 10 หลายเดือนก่อน +10

    With the roots you just have to write e^1/2 = 6th-root(e^3) and e^1/3 = 6th-root(e^2). You can multiply both and get 6th-root(e^5) and conclude. The method can be generalized to every rational powers

    • @mozvi1436
      @mozvi1436 10 หลายเดือนก่อน

      What about transcendental powers?

    • @romain.guillaume
      @romain.guillaume 10 หลายเดือนก่อน

      @@mozvi1436 as I said this method is generalizable to rational, not even algebraic numbers. Although it may be possible to find a proof involving some kind of polynomial decomposition for algebraic numbers, transcendental one cannot work with this method I guess. Maybe using some kind of series it is possible to get a similar proof but first I am too lazy to check that, second it would be nice to see if it already work with algebraic ones.

    • @stevenfallinge7149
      @stevenfallinge7149 10 หลายเดือนก่อน +1

      @@romain.guillaume One can first prove it's continuous on the rationals, and use this to extend it to the reals and prove the property holds by convergent sequences.

    • @romain.guillaume
      @romain.guillaume 10 หลายเดือนก่อน

      @@stevenfallinge7149 if it works showing continuity on algebraic numbers, it could the same way be extend to all complex number also 👍

  • @JSSTyger
    @JSSTyger 10 หลายเดือนก่อน +2

    Now do 2+2 using advanced calculus please. :D

    • @keescanalfp5143
      @keescanalfp5143 10 หลายเดือนก่อน

      when there is a short way, why would not you choose the long way to tipperary .

  • @alexandermcclure6185
    @alexandermcclure6185 10 หลายเดือนก่อน

    me, just using (x^h)(x^k)=x^(h+k): what's the issue?

  • @romanbykov5922
    @romanbykov5922 10 หลายเดือนก่อน

    But why wouldn't you use n in the second series? I don't see a problem with that, because it's the same natural number.

  • @syedmdabid7191
    @syedmdabid7191 9 หลายเดือนก่อน

    Valde facilis! His est e^5/6= Anti-ln 0. 83 responsi.hic est√√√🎎

  • @bengt-goranpersson5125
    @bengt-goranpersson5125 10 หลายเดือนก่อน

    Somewhere around 8:50 I just saw nested for-loops in my head. :)

  • @seja098
    @seja098 10 หลายเดือนก่อน

    there are other ways to describe this without using 15 minutes (with calculus).

  • @user-sr6ig3xk9x
    @user-sr6ig3xk9x 10 หลายเดือนก่อน

    Simple made complicated. How is this different from adding the indices as before?

  • @MindHaunter
    @MindHaunter 6 หลายเดือนก่อน

    Would solve this: if x^2 + x + 1 = 0, then solve x^49 + x^50 + x^51 + x^52 + x^53 = ?

  • @lornacy
    @lornacy 7 หลายเดือนก่อน

    Math is life, life is math. The simplest of things can be made so much more complicated!

  • @quentinrenon9876
    @quentinrenon9876 10 หลายเดือนก่อน +1

    We had to figure exactly that in an analysis I exercice once. It's very cool

  • @TheMasterGreen
    @TheMasterGreen 9 หลายเดือนก่อน

    14:44 (answer is 14).
    The way I solved it:
    If u look at all the vertical sums, each one has a star so we can ignore it and conclude that 2 circle = 2 square + 2 and likewise, 2 triangle = 2 square + 6.
    divide both equations by 2 we get --> c = s + 1 and t = s + 3. Now I looked at the middle horizontal sum in terms of square (s) and got 3s + 4 = 19 so s = 5.
    This means triangle = 8 and circle = 6, and after plugging into to a different sum I found star = 3. then I am done. 6 + 5 + 3 = 14.

  • @ВикторПоплевко-е2т
    @ВикторПоплевко-е2т 10 หลายเดือนก่อน

    2:02 not 0, because there will be 0^0, which is undefined

  • @ВикторПоплевко-е2т
    @ВикторПоплевко-е2т 10 หลายเดือนก่อน

    2:02 not 0, because there will be 0^0, which is undefined

  • @electrogadgets6170
    @electrogadgets6170 10 หลายเดือนก่อน

    Nice proof.
    I'll just work it using the product law for exponents:
    e^(1/2) + e^(1/3)
    = e^((1/2)+(1/3))
    = e^((3/6)+(2/6))
    = e^(5/6)

  • @marcelovsrj
    @marcelovsrj 10 หลายเดือนก่อน

    Ladys and Gentlemen: This is exactly a nuke to kill a bee

  • @maxhagenauer24
    @maxhagenauer24 10 หลายเดือนก่อน +8

    Product of a Power rule from elementary school left the chat.

    • @Dhruv2107
      @Dhruv2107 10 หลายเดือนก่อน +11

      The video is about proving that rule bruh

    • @maxhagenauer24
      @maxhagenauer24 10 หลายเดือนก่อน +1

      @Dhruv2107 It isn't proving that. He's showing it just for this specific case with e's that it works his ways but that doesn't mean it works for any base. He's showing it for 1 specific problem. There are actual ways to prove the product of a power rule that are really easy.

    • @Dhruv2107
      @Dhruv2107 10 หลายเดือนก่อน +3

      @maxhagenauer24 it's not just about that case . For example I learned the product of 2 summations in a different way then I know . Idk about you but I learned quite a lot from this video

    • @raviishpanicker7729
      @raviishpanicker7729 10 หลายเดือนก่อน +4

      @@maxhagenauer24 A number in any base can be converted to base e, so he is proving it for every case. For example, 2^x = (e^ln2)^x = e^(xln2).

    • @maxhagenauer24
      @maxhagenauer24 10 หลายเดือนก่อน

      @raviishpanicker7729 Sure but he didn't prove the rule, he just solved it a different way.

  • @hermannschaefer4777
    @hermannschaefer4777 6 หลายเดือนก่อน

    I feel dumb now, I just added 1/2 and 1/3..

  • @abrahamplasencia2611
    @abrahamplasencia2611 10 หลายเดือนก่อน +1

    what a way of overkill, try better prooving that (e^x)(e^y)=e^(x+y) if x and y commute

    • @blackpenredpen
      @blackpenredpen  10 หลายเดือนก่อน +1

      not sure why we need x and y commute but I actually made that video before this one:
      th-cam.com/video/r87AfxUwD60/w-d-xo.html

    • @abrahamplasencia2611
      @abrahamplasencia2611 10 หลายเดือนก่อน

      @@blackpenredpen then why you overkill the 1/2+1/3 man 😭

    • @abrahamplasencia2611
      @abrahamplasencia2611 10 หลายเดือนก่อน +1

      @@blackpenredpen and, in fact if x and y are matrices and they dont commute (as usual) e^x e^y
      eq e^(x+y)

  • @cob180-h3y
    @cob180-h3y 10 หลายเดือนก่อน

    Gap year any math competition held for participate

  • @geetaborban8110
    @geetaborban8110 10 หลายเดือนก่อน

    Sir please can you solve this question

  • @MDSiam-ek9km
    @MDSiam-ek9km 10 หลายเดือนก่อน

    Oh wow! I can finally show my 6th grader why e^(1/2)*e^(1/3) equals e^(5/6)!😀😀😀😀 (no offense)

  • @devathadevi
    @devathadevi 10 หลายเดือนก่อน

    Please do hard questions on continuity and diffrentiability please I'm facing problem 🙏🙏🙏🙏😓😓😓

  • @guilhermerocha2832
    @guilhermerocha2832 10 หลายเดือนก่อน

    Or How to Kill a Mosquito with a Shotgun

  • @Anonymous-nt8ui
    @Anonymous-nt8ui 10 หลายเดือนก่อน

    Can you solve this question please
    Determine whether the series converges or diverges
    Summation (2+(-1)^n)/√n.3^n

  • @scottleung9587
    @scottleung9587 10 หลายเดือนก่อน +1

    Nice proof!

  • @Bbbbbx
    @Bbbbbx 6 หลายเดือนก่อน

    i was halfway through the vid and when you introduced the 2nd note, i was like "hmm, this suspiciously looks that formula from counting". glad that i was able to recognized it

  • @duckimonke
    @duckimonke 10 หลายเดือนก่อน +1

    second

  • @PrairieWolf-xo8yx
    @PrairieWolf-xo8yx 10 หลายเดือนก่อน

    fabulous! thanks for sharing

  • @jeeum
    @jeeum 10 หลายเดือนก่อน

    "Don't say two over five" 😂😂😂

  • @MeQt
    @MeQt 10 หลายเดือนก่อน

    That thumbnail goes hard

  • @charliearmour1628
    @charliearmour1628 9 หลายเดือนก่อน

    The comments are almost as good as the video 😊.

  • @LuigiElettrico
    @LuigiElettrico 10 หลายเดือนก่อน

    Just like that.

  • @tobybartels8426
    @tobybartels8426 10 หลายเดือนก่อน +6

    You can do it with √e and ³√e. Just raise √e × ³√e to the power of 6 by repeated multiplication, group √e together in groups of 2 and ³√e together in groups of 3 to get e, and you'll see that you have e×e×e×e×e. So (e^½ × e^⅓)^6 = e^5, which means (since e^½ × e^⅓ is positive) that e^½ × e^⅓ = e^⅚.

    • @XtronePlaysG
      @XtronePlaysG 10 หลายเดือนก่อน +3

      Wouldn't this be using what we want to prove though? since you are using (A^m)^n = A^mn which is just repeated addition of the exponents i.e. A^(m+m+m..) n times

    • @tobybartels8426
      @tobybartels8426 10 หลายเดือนก่อน

      @@XtronePlaysG : I'm taking the definition of a^(5/6) to be the positive number x such xxxxxx=aaaaa, that is, a^(5/6) := ⁶√(a⁵). It's true that this definition is motivated by the property that you mentioned, but we have to define it somehow, and this seems to me to be the standard definition.

  • @Tritibellum
    @Tritibellum 10 หลายเดือนก่อน

    the e^x taylor series got me

  • @matheusdossantos9252
    @matheusdossantos9252 10 หลายเดือนก่อน +1

    Hi bprp, good video! I have a video suggestion:
    All solutions of the equation sqrt(x^x) = x^sqrt(x)

    • @atifashhabatif8391
      @atifashhabatif8391 10 หลายเดือนก่อน +1

      Isn't that just x= 0 and 4?? (Dunno bout the complex ones)

    • @jacobgoldman5780
      @jacobgoldman5780 10 หลายเดือนก่อน +1

      @@atifashhabatif8391 not 0 as 0^0 is undefined... also you forgot about x=1

    • @matheusdossantos9252
      @matheusdossantos9252 10 หลายเดือนก่อน +1

      @@atifashhabatif8391Yes, is x=1 and x=4 in the real world, but want to see the complex world

  • @易利亚
    @易利亚 3 หลายเดือนก่อน

    Im going to use this on my assignment..

  • @_elusivex_
    @_elusivex_ 10 หลายเดือนก่อน

    it sounded me like a nested for-loop.

  • @1234thecreator
    @1234thecreator 9 หลายเดือนก่อน

    me : 1/2+1/3 = 3/6+2/6 = 5/6

  • @michaelsanchez7798
    @michaelsanchez7798 10 หลายเดือนก่อน

    When I saw the title to this video, I was disappointed. I clicked on it just so I could complain that this is not what I watch your channel for. However, you did not disappoint. Cool approach.

  • @Guidussify
    @Guidussify 4 หลายเดือนก่อน

    So we do just add the powers. Wow. I first I thought it must be a trick question.

    • @Unlimit-729
      @Unlimit-729 2 หลายเดือนก่อน

      e^(1/2) * e^(1/3)
      Next step:
      e^(3/6) * e^(2/6)
      Next step:
      e^(5/6)
      Answer:
      e^(5/6)

  • @Avighna
    @Avighna 7 หลายเดือนก่อน

    This can also be used as a proof of the binomial theorem, which is a really cool side effect. Love these videos man.

  • @sebastienlecmpte3419
    @sebastienlecmpte3419 10 หลายเดือนก่อน +1

    Small correction: that power series is true for all x EXCEPT 0.

    • @Eye-vp5de
      @Eye-vp5de 10 หลายเดือนก่อน

      Why? 0^0 can be defined as 1

    • @sebastienlecmpte3419
      @sebastienlecmpte3419 10 หลายเดือนก่อน

      @@Eye-vp5de 0^0 is undefined

    • @Eye-vp5de
      @Eye-vp5de 10 หลายเดือนก่อน

      @@sebastienlecmpte3419 this depends on definition, that's why I said that it can be defined as 0

    • @sebastienlecmpte3419
      @sebastienlecmpte3419 10 หลายเดือนก่อน

      @Eye-vp5de I would be curious to see a recognized dedinition of 0^0 to be one.
      I mean I can define 2+2 to be equal to 5 if I want, that does not make it true.

    • @keescanalfp5143
      @keescanalfp5143 10 หลายเดือนก่อน

      ​@@sebastienlecmpte3419,
      note that this exp-question might be not about
      0^0 , but about the function
      exp (x) , so
      exp (0) , or
      e^(0) ,
      which is by definition = 1.
      because the inverse,
      ln (1) = 0 , isn't this the integration from 1 to 1 of the function 1/x .

  • @cegexen8191
    @cegexen8191 10 หลายเดือนก่อน

    0:54 THAT KILLED ME SO MUCH LMAO

  • @lasinhouseinthetrees1928
    @lasinhouseinthetrees1928 10 หลายเดือนก่อน

    Hey blackpenredpen congrats on your sponsor genuinly hie do you feel about brilliant ive seen it sponsored so many times and i thought it might be s good gateway into higher levelsnof math so i could go over it before going into calculus :)

  • @thatomofolo452
    @thatomofolo452 10 หลายเดือนก่อน

    Of course 💯

  • @mprziv
    @mprziv 10 หลายเดือนก่อน

    Because 1/2+1/3 = 5/6 ?

  • @ettoremaxdilena5479
    @ettoremaxdilena5479 9 หลายเดือนก่อน

    I want the shirt. Now.

  • @thatapollo7773
    @thatapollo7773 10 หลายเดือนก่อน

    I rember doing this! I was wondering how you wold deriveve exp(a+b) from the power series and I created a similar proof