(√1995)·x^(log₁₉₉₅ x) = x²

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  • Опубліковано 10 тра 2024
  • In this video I solved an exponential logarithmic radical equation using basic algebra knowledge. This was from 1995 AIME.

КОМЕНТАРІ • 32

  • @allozovsky
    @allozovsky 22 дні тому +17

    We can add some nice Unicode typesetting to the title:
    *(√1995)·x^(log₁₉₉₅ x) = x²*

    • @allozovsky
      @allozovsky 22 дні тому +2

      I don't know if the "vinculum" in *√1̅9̅9̅5̅* would be visible on all devices, though 🤔

    • @PrimeNewtons
      @PrimeNewtons  22 дні тому +6

      Thank you

  • @narhumo7497
    @narhumo7497 22 дні тому +14

    Oh wow the mod was awesome, very well explained sir. This is a great problem to test algebraic skill. I really like how it wraps up to be 1995^2, it gets so simple from something so disturbingly complicated at first glance

    • @nicolascamargo8339
      @nicolascamargo8339 22 дні тому +2

      With square difference it is also possible to calculate 1995² quickly

    • @dirklutz2818
      @dirklutz2818 22 дні тому +3

      @@nicolascamargo8339 Indeed! 1995² = (2000-5)² = 2000² - 20000 + 25, so the last three digits are 025.

    • @PrimeNewtons
      @PrimeNewtons  21 день тому +2

      Smart

  • @majora4
    @majora4 21 день тому +2

    What I love most about this problem is how generalizable it is. You can replace 1995 with any number y > 1 and the product of the positive roots will always be y^2. Moreover, you can always replace the exponent on the right-hand side with any number z > sqrt(2)* and the product of the positive roots will always be y^z.
    *If you set z = sqrt(2) there will be only one root... but it has multiplicity 2 and it value is exactly sqrt(y^z) so you can make an argument that the product should still be considered y^z

  • @marcolima89
    @marcolima89 22 дні тому +3

    this guy has genuinely rekindle my interest in math
    thank you for doing this and please keep doing it.

  • @toastdog214
    @toastdog214 22 дні тому +3

    I tried doing it myself and I got to 1995², and I was stumped on how to get the last 3 digits. I ended up just doing regular multiplication, but wow the solution you have given here is genius! mod 1000 would've never crossed my mind

  • @Moj94
    @Moj94 22 дні тому +4

    I tried doing it myself and I decided I'd rather stay an infant.

  • @davidgagen9856
    @davidgagen9856 21 день тому

    Brilliant explanation.

  • @souverain1er
    @souverain1er 20 днів тому

    Awesome Prof.!

  • @YAYAMEDIA-su8up
    @YAYAMEDIA-su8up 22 дні тому +1

    I love you so much and am from mom Ethiopia

  • @mudspud
    @mudspud 22 дні тому +1

    Fascinating

  • @Happycurv
    @Happycurv 22 дні тому +1

    I'm impressed with how far I got. The question confused me I guess though

  • @Arkapravo
    @Arkapravo 22 дні тому

    weird question, cool solution!

  • @JEEAspirant1738
    @JEEAspirant1738 21 день тому

    sir I didn't understand the part where you put mod 1000. Please explain it to me in the comments.

  • @jamesharmon4994
    @jamesharmon4994 22 дні тому

    Since you have two roots, both positive, wouldn't you have three possible products? (Root 1)^2, (Root2)^2, (Root1)(Root2)??

  • @souverain1er
    @souverain1er 20 днів тому

    I think the last 3 digits of the product of the positive roots is 1995^2 (mod 1000), which equals (1995 mod 1000)^2 using modular exponent property. You skipped a step.

  • @spartan246
    @spartan246 16 днів тому

    This god is a goddam wizzard

  • @SiladityaSen1993
    @SiladityaSen1993 17 днів тому

    Isnt doing the (2000-5)^2 be easier?

  • @wiafesamuel-xi8cl
    @wiafesamuel-xi8cl 17 днів тому

    Please help me these questions. x to the power x equal to 3 to the power 81
    another one is x to the power x equal to 2 to the power 64
    and lastly, x to the power x equal to 2 to the power 1024.

  • @JCSol
    @JCSol 22 дні тому

    crazy

  • @Adam-pj2qh
    @Adam-pj2qh 22 дні тому

    wow thats clever

  • @Ron_DeForest
    @Ron_DeForest 22 дні тому +2

    How is it you can just say the base is 1995? Isn’t the base automatic 10? If you’re changing the base, don’t you have to do shit to the argument? Am I writing this correctly?

    • @vojtatheguitargeek
      @vojtatheguitargeek 22 дні тому +1

      yeah he could have already written it in the first step...he basically took log base 1995 of both sides of the equation, but firstly thought of using regular log and then he decided to change the base afterwards and didn't come back to rewrite it everywhere. as far as i know you don't have to mess with the argument if you choose whatever base you like (as long as you apply the same log to both sides).

    • @knupug
      @knupug 22 дні тому +4

      The base of the log function can be anything. It simply asks what power of the base will equal the argument. The ln function is log base e. Log to the base 2 of 8 is 3. Log to the base 10 of 100 is 2. So, to solve this problem, he took log to the base 1995 of both sides.

    • @sphakamisozondi
      @sphakamisozondi 22 дні тому +1

      If u introduce log, u can use any base of your choice.
      If u want to do it the long way around. U can use base 10, then do change of Base, and u will arrive to the same approach but with extra steps.
      He just skipped two steps in order to use base 1995. But if u are comfortable with the base 10 approach then apply change of Base procedure, u can do so.

    • @aguyontheinternet8436
      @aguyontheinternet8436 22 дні тому +1

      if y=x, then log(y)=log(x), regardless of the base you choose. You can go back and change the base as many times you want, the equation will still hold true