How to solve exponential equations (10 examples from easy to hard!)

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  • Опубліковано 9 лис 2024

КОМЕНТАРІ • 71

  • @albertoesquivias6073
    @albertoesquivias6073 7 місяців тому +46

    Please do more of these "how to solve" type of videos and I hope it becomes a series, it was really easy to follow

    • @bprpmathbasics
      @bprpmathbasics  7 місяців тому +17

      I plan to. Glad to hear they are helpful! Thanks.

    • @kingsan3162
      @kingsan3162 5 місяців тому

      @@bprpmathbasics Hello,thank you so much and i consider you a teacher of mine even though i never met you live.
      But i wanna ask you if you can do 2 examples of 1 equation.
      Becuase in that case it helps anyone see the bigger picture.

  • @TerraBlo
    @TerraBlo 7 місяців тому +38

    12:20
    I love how he shows these random bloopers

    • @lotaniq4449
      @lotaniq4449 7 місяців тому +1

      its an accident lol

    • @TerraBlo
      @TerraBlo 7 місяців тому

      @@lotaniq4449 he does it quite a lot

    • @TerraBlo
      @TerraBlo 7 місяців тому

      @@lotaniq4449 he did mean it he puts it on some other videos sometimes

    • @tfg601
      @tfg601 2 місяці тому

      I don't get it

  • @euloge996
    @euloge996 7 місяців тому +24

    12:19 lazy editing😂
    love you bro

  • @fireball54110
    @fireball54110 7 місяців тому +91

    -okay, number 6-

    • @nicholaslama6670
      @nicholaslama6670 7 місяців тому +19

      Bro, I got so confused, I thought I was having some recurring déjà vu's

    • @idontcareforthis
      @idontcareforthis 7 місяців тому

      @@nicholaslama6670No déjà-vu for me, but I was on the verge of cursing at my phone for glitching.

    • @charg1nmalaz0r51
      @charg1nmalaz0r51 6 місяців тому +7

      @@nicholaslama6670 got stuck in the worst version of groundhog day 🤣

  • @pedrogarcia8706
    @pedrogarcia8706 7 місяців тому +9

    11:15 you can also use ln(pos)/ln(b). most calculators with have natural log in addition to log base 10.

    • @ronaldjensen2948
      @ronaldjensen2948 7 місяців тому

      For me this was more intuitive. we just go from x ln(5) = ln(2) to x = ln(2)/ln(5)

    • @Erlewyn
      @Erlewyn 7 місяців тому +1

      That's actually how I was taught 20+ years ago, in high school in France. I don't think you even learn about different bases log before college here.

  • @epicstar86
    @epicstar86 7 місяців тому +6

    for question 6 I used exponential properties before logarithmic ones

  • @sankaranbs4024
    @sankaranbs4024 7 місяців тому +34

    I thought, I have I Internet problem with 'Okay, number 6 what's e though'

  • @TheZmoliver
    @TheZmoliver 5 місяців тому +1

    You take the stress out of math, man. Thank you!

  • @barryspindler8342
    @barryspindler8342 5 місяців тому +1

    excellent job and done at the right pace. I like your work.

  • @the_m_original
    @the_m_original 28 днів тому

    for question 9, here is the imag solution:
    e^x = -3
    x = ln(-3) ; ln both sides
    x = ln(3*-1) ; factorize -3
    x = ln(3) + ln(-1) ; split
    x = ln(3) + ln(e^iTheta) ; let e^iTheta = -1, and Theta be equal to Pi + 2nPi where n is any positive integer
    x = ln(3) + i(Pi+2nPi)

  • @DrTWG
    @DrTWG 6 місяців тому

    You are teaching a lot of people some great maths skills .

  • @Fenamer
    @Fenamer 7 місяців тому +3

    Can you make more ''How to solve' videos? I think these videos are easy to follow through, and I want more so I can learn bits of precalc and calc.

  • @bencepaul3497
    @bencepaul3497 29 днів тому

    Thanks so much for your videos! I really get a lot out of them!!

  • @HimanshuYadav-v3r
    @HimanshuYadav-v3r 6 місяців тому +1

    i am promoted to class 10th 2 months ago and i solved all. I cant believe it.

  • @leonardobarrera2816
    @leonardobarrera2816 7 місяців тому +1

    Exponential equations are so easy that I have never saw on my college and I can solve all of them!!!

  • @RedoanaSultana
    @RedoanaSultana 7 місяців тому

    Question 7:
    3^(x-2) = 5^(x+4)
    (3/5)^x = 5^4 * 3^2
    x = log(5^4 * 3^2)/log(3/5)
    Question 8:
    7^(2x-1) = 2^(4x+3)
    (7/4)^(2x) = 2^3 * 7
    2x = log(2^3 * 7)/log(7/4)

  • @klmcwhirter
    @klmcwhirter 7 місяців тому +1

    Love the video.
    But I saw you miss this a couple of times now.
    The reason the exponential property of same bases works is because if you take the log of both sides they cancel. _Note I saw you covered this later, but it would be helpful to explain in problem 1._
    2^(3X+1) = 2^5
    log₂ 2^(3X+1) = log₂ 2^5 (how do I do strikeout in a comment?)
    Which leaves you with ...
    3X+1 = 5
    Heads up - that extra explanation will make things clearer for some students.
    Great job though. I love your videos!

    • @cheeseplated
      @cheeseplated 7 місяців тому +1

      -for strikethrough- put - on either end of the text
      _for italics_ it's _
      *for bold* it's *
      *_-and you can combine them-_*

    • @bprpmathbasics
      @bprpmathbasics  7 місяців тому

      Thank you!

    • @Apollorion
      @Apollorion 7 місяців тому

      The reason that that 'exponential property of same bases' works is that:
      A: the base is bigger than 0 as well as well unequal to 1
      and
      B: if y=a^x and z=dy/dx then z is unequal to 0 and has a constant sign (i.e. d( z/|z| )/dx = 0 no matter the value of x) which implies that for an increase in x, y is always bigger (for a>1) or smaller (for a

  • @suchaluch5615
    @suchaluch5615 7 місяців тому +1

    Great presentation!
    Thanks

  • @GirishManjunathMusic
    @GirishManjunathMusic 7 місяців тому +2

    Before watching the video:
    Question 1:
    2↑(3x + 1) = 32
    We know that 32 = 2⁵
    2↑(3x + 1) = 2⁵
    Comparing like terms:
    3x + 1 = 5
    3x = 4
    x = 0.75.
    Question 2:
    27↑x = 9↑(2x - 3)
    27 = 3³ and 9 = 3²:
    3↑3x = 3↑(4x - 6)
    Comparing like:
    3x = 4x - 6
    x = 6.
    Question 3:
    5↑(x² + 3x - 4) = 1
    But 5⁰ = 1:
    5↑(x² + 3x - 4) = 5⁰
    Comparing like:
    x² + 3x - 4 = 0
    x² + 4x - x - 4 = 0
    (x + 4)(x - 1) = 0
    x = -4, x = 1.
    Question 4:
    (√2)↑(x + 4) = ⅛
    But ⅛ = 8↑(-1), 8 = 2² and √2 = 2↑½:
    2↑(½x + 2) = 2↑(-3)
    Comparing like:
    ½x + 2 = - 3
    ½x = -5
    x = -10.
    Question 5:
    5↑x = 2
    xln5 = ln2
    x = ln2/ln5.
    Question 6:
    20e↑(3x - 2) = 1200
    e↑(3x - 2) = 60
    3x - 2 = ln(60)
    x = ⅓(ln(60) + 2).
    Question 7:
    3↑(x - 2) = 5↑(x + 4)
    (x - 2)ln3 = (x + 4)ln5
    xln3 - 2ln3 = xln5 + 4ln5
    x(ln3 - ln5) = 2ln3 + 4ln5
    x = (2ln(3) + 4ln(5))/(ln(3) - ln(5)).
    Question 8:
    7↑(2x - 1) = 2↑(4x + 3)
    (2x - 1)ln7 = (4x + 3)ln2
    2xln7 - ln7 = 4xln2 + 3ln2
    x(2ln7 - 4ln2) = (3ln2 + ln7)
    x = (3ln2 + ln7)/(2ln7 - 4ln2).
    Question 9:
    e↑2x + e↑x - 6 = 0:
    Setting e↑x = t → e↑2x = t²:
    t² + t - 6 = 0
    t² + 3t - 2t - 6 = 0
    (t + 3)(t - 2) = 0
    t = -3 or t = 2
    But as t = e↑x; t > 0:
    t = 2 → e↑x = 2
    x = ln2.
    Question 10:
    2↑x + 3·2↑(-x) = 4
    Setting 2↑x = t → 2↑(-x) = 1/t:
    t + 3/t = 4
    t - 4t + 3 = 0
    t - 3t - t + 3 = 0
    (t - 1)(t - 3) = 0
    t = 1 or t = 3.
    But t = 2↑x:
    Case 1: t = 1:
    2↑x = 1
    x = 0.
    Case 2: t = 3:
    2↑x = 3
    xln2 = ln3
    x = ln(3)/ln(2).

    • @Apollorion
      @Apollorion 7 місяців тому

      I think you made a pair of typo's in Question 10; after multiplying the whole equation with t, t does not turn into t² whereas it should and is also processed as.

    • @GirishManjunathMusic
      @GirishManjunathMusic 7 місяців тому

      @@Apollorion so I have! The radical must not have entered properly, I'm typing these on the phone keyboard, so those radicals are sometimes difficult to enter!

    • @Apollorion
      @Apollorion 7 місяців тому

      @@GirishManjunathMusicWell, bless UA-cam. /s
      If I made a 'mistake' from the perspective of the 'algorithm' then I want to know how/why and not a brutal disappearance without explanation; I want to learn from my mistakes to avoid to repeat them.
      P.S.
      b.t.w. you might help yourself with copy & paste or describing t squared with other symbols e.g. t^2 or tt.

    • @thewendigo9263
      @thewendigo9263 6 місяців тому +1

      You made a mistake on question one. X is 1.33

    • @Apollorion
      @Apollorion 6 місяців тому

      @@thewendigo9263I agree with the mistake you seem to notice (i.e. 3x=4 => x=4/3) but not with the alternate solution you propose i.e. 1.33
      _It is more accurate but still not correct_ . The correct solution in expressed in decimals would finish with an infinite amount of 3s after the dot, not just two.

  • @Gremriel
    @Gremriel 7 місяців тому +1

    Most of what you talk about goes over my head, but occasionally I learn something.

  • @ghostkiller4071
    @ghostkiller4071 7 місяців тому +2

    Thanks for everything

    • @penguin9257
      @penguin9257 7 місяців тому

      This sounds concerning

  • @gigi4874-w3w
    @gigi4874-w3w 7 місяців тому

    Fantastic review! 🙏🏽👏🏽

  • @DominickRiesland
    @DominickRiesland 7 місяців тому +2

    What do you do when the teacher tells you to express the answer to #7 and #8 as a single logarithmic function? 😂

    • @bprpmathbasics
      @bprpmathbasics  7 місяців тому +1

      Show them this video: ua-cam.com/video/WVGZbO0esOM/v-deo.html
      : )

  • @javier-kk4eq
    @javier-kk4eq 17 днів тому

    here 7 months later great video

  • @axn_anime
    @axn_anime 4 місяці тому

    Can you please do one for trigonometry 🥺❤️

  • @cdkw8254
    @cdkw8254 7 місяців тому

    Where is the 25 find the range of function questions? You said you would upload that in your 25 trig questions video.

  • @fullc0de
    @fullc0de 7 місяців тому +1

    @4:46 OMG, I know that 5^0 = 1. How did I not see that I needed to use that when I tried the problem before I watched you solve it?????

    • @darranrowe174
      @darranrowe174 7 місяців тому +1

      Sometimes these facts are so simple, we miss them.
      When I was younger, I know I often saw equality as a one way thing so I could apply it one way but never thought about applying it the other. This is why videos like this can be good. It makes you think of things in ways you never thought of before.

    • @fullc0de
      @fullc0de 7 місяців тому

      @@darranrowe174 When you do make the connection and see how the puzzle piece fits, it's such a great feeling, no matter how simple the insight is! When you don't, it's a total Homer Simpson '"D'oh!" moment! The drama of math.

  • @fromscratch8774
    @fromscratch8774 4 місяці тому

    For 9: e^2x + e^x - 6 = 0
    why wouldn't collecting like terms and using ln on both sides work?

  • @lucaspheng6009
    @lucaspheng6009 Місяць тому

    Why not just use the division rule for the logs with negatives?

  • @SuperTommox
    @SuperTommox 7 місяців тому +2

    Can you solve log(x)=x?

    • @cdkw8254
      @cdkw8254 7 місяців тому +1

      e^x

    • @cpu_1292
      @cpu_1292 7 місяців тому

      You raise x by both sides to get x^log(x) = x^x
      The log and the x cancels out so you get x = x^x
      x has to be one because 1 = 1^1
      Edit: I made a mistake, there is no real solution
      Edit2: here is the real solution
      Raise 10 by both sides and get 10^log(x) = 10^x
      The 10 and the log cancel out to get x = 10^x so there is no real solution

    • @stolen-flame2025
      @stolen-flame2025 7 місяців тому +1

      @@cpu_1292 i think thats wrong bc log(1)=0 [10^0=1]

    • @stolen-flame2025
      @stolen-flame2025 7 місяців тому +1

      no real solutions

    • @xinpingdonohoe3978
      @xinpingdonohoe3978 7 місяців тому +1

      Not in the real plane. This can be shown by knowing ln(x)=x is the same as x=e^x.
      x2>1 means e^x>2^x, so e^x>x, so x>ln(x).

  • @euloge996
    @euloge996 7 місяців тому +1

    i love you brro

  • @rangga2397
    @rangga2397 7 місяців тому

    5:16 i factor (x-3) (x-1) am i wrong?

    • @zilovesmaths
      @zilovesmaths 6 місяців тому +2

      Ah you've done it the other way around
      To factor it you need 2 numbers that multiply to give c (-4)
      And they need to add to give b (+3)
      You've got 2 numbers that multiply for b and add for c haha
      So if you expand (x-3)(x-1)
      That gives x²-4x+3 instead of x²+3x-4

  • @kloneo
    @kloneo 6 місяців тому +1

    It would be nice if people could download a questions sheet of the shown equations but with the numbers changed. To think at home and rewatch your explanation to complete the question. Make a +2 a +5. Something like that for the video questions. The next video give the answers as a 2 sec show frame before the new vid. Mayby win something, Or on patreon or something.

  • @fizisistguy
    @fizisistguy Місяць тому +1

    This was clearly not a basic to hard one.
    😅

  • @ssdrxgod
    @ssdrxgod 7 місяців тому

    ~I Found All Of Them Ez

  • @DokkanPapaya
    @DokkanPapaya 7 днів тому

    So this and that cancel

  • @donwald3436
    @donwald3436 7 місяців тому

    and as always that's it lol.

  • @Robin-Dabank696
    @Robin-Dabank696 7 місяців тому +2

    Can you please upload more on your main channel? I miss the exciting content on that channel