Logarithms Part 1: Evaluation of Logs and Graphing Logarithmic Functions

What are logs? No not like the ones from trees, silly! We need to know about logarithms. They represent the inverse operation of exponentiation. How do they work? How do we evaluate them? How do we graph them? Let's go through the basics now.
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Пікірлер: 69

  • @ProfessorDaveExplains
    @ProfessorDaveExplains5 жыл бұрын

    Whoops! At 0:50, I meant to show an exponential equation, like 2^x, instead of x^2, as 2^x is the proper inverse of log base 2 of x. Sorry!

  • @ramayanishukla4365

    @ramayanishukla4365

    4 жыл бұрын

    Happens

  • @angelisvegan5826

    @angelisvegan5826

    3 жыл бұрын

    @Dhruv Chaturvedi exactly.. I'm confused.. totally confused

  • @angelisvegan5826

    @angelisvegan5826

    3 жыл бұрын

    Help me professor.. I ain't getting that 2:51 point.. log base b of (y) = x should be the inverse function of y=b^x.. And look what you've written

  • @randypreston9377

    @randypreston9377

    2 жыл бұрын

    you all prolly dont care but does any of you know a tool to log back into an Instagram account? I somehow forgot my login password. I love any assistance you can give me

  • @samirmanuel8944

    @samirmanuel8944

    2 жыл бұрын

    @Randy Preston instablaster =)

  • @enzoqueijao
    @enzoqueijao4 жыл бұрын

    This is the point where mathematicians got tired of creating signs for their operations and just gave up

  • @youtubeuserdan4017

    @youtubeuserdan4017

    Жыл бұрын

    Imagine if addition looked like add(5,3)=8

  • @fusion_42

    @fusion_42

    Жыл бұрын

    ​@@youtubeuserdan4017👏

  • @ivoryas1696

    @ivoryas1696

    10 ай бұрын

    enzoqueijao Eh, _close._

  • @HAAH999
    @HAAH9995 жыл бұрын

    You need to edit the video at 0:50, such that 2^x is the inverse of log_2(x) instead of x^2. However, this was an excellent explanation

  • @ProfessorDaveExplains

    @ProfessorDaveExplains

    5 жыл бұрын

    I can't edit videos once they're posted. I didn't specifically state that the functions are inverses, but I do see how what is shown is misleading. I pinned a comment so hopefully people will catch that!

  • @Solicanz
    @Solicanz Жыл бұрын

    you are a genius, feynman level explaination, this concept finally clicked for me

  • @simonoraha
    @simonoraha6 жыл бұрын

    Love your videos! Keep it up!

  • @pinklady7184
    @pinklady71843 жыл бұрын

    I am here, just revising my studies of logarithm. I hope you will make a playlist of logarithms.

  • @AriaHarmony
    @AriaHarmony6 жыл бұрын

    Thank you for including graphing in your videos! The concept that all graphs can be seen as transformations of their most basic form is very important to me, it gives me a very good intuition on the equations and how they relate to their graphs. I have a question, at 2:57 that part always confuses me, why is it that b and x must always be positive? is -3^3 = -27 non-existent in the world of logs??

  • @ProfessorDaveExplains

    @ProfessorDaveExplains

    6 жыл бұрын

    It's a good question! It's simply that only for the set of positive bases can a function be continuous, so we just focus on what is mathematically useful.

  • @AriaHarmony

    @AriaHarmony

    6 жыл бұрын

    Oh I see! I didn't notice that something like -3^x wouldn't be continuous.. Thanks!

  • @fernandoportal5422
    @fernandoportal5422 Жыл бұрын

    Thank you so much, i was struggling with this, but this video made it work

  • @himanivachhani5575
    @himanivachhani55755 жыл бұрын

    I love this thank you so much

  • @user-hv6ef9ie1g
    @user-hv6ef9ie1g4 ай бұрын

    For anyone who's confused about 2:51 (That he should've wrote log base b of (y) =x), he explained it in 2:21 (How the inverse was derived)

  • @muskanmishra5581
    @muskanmishra5581 Жыл бұрын

    Kya baat hai sir!!! Bohot badhiyaa

  • @MajedSalmaoun
    @MajedSalmaoun7 ай бұрын

    bro you are a legend i wish i knhow this channel before All Love For You

  • @Ereh729
    @Ereh72911 ай бұрын

    Taking precalc rn. You're a life saver.

  • @Morfeucomvoce
    @Morfeucomvoce6 жыл бұрын

    Good video!

  • @diaverna
    @diaverna6 жыл бұрын

    Can you please make a video on Fluid Mechanics? 😭

  • @gokucrafter9456
    @gokucrafter94562 жыл бұрын

    I have a question, How do you solve (-2)^x=-8, I know the answer is 3 and know the workaround, but cannot solve it only using logarithm's definition.

  • @literallyfornobigreason9432
    @literallyfornobigreason94323 жыл бұрын

    Thanks king

  • @jaineilsart1528
    @jaineilsart1528 Жыл бұрын

    Even dave the professor makes mistakes. He taught me more than math today.

  • @ericard4165
    @ericard41656 жыл бұрын

    Is this video made by yourself? Awesome

  • @nbthakar
    @nbthakar6 жыл бұрын

    Great video and work, as always Prof. Dave!! Quick question for you. At the 0:51 mark, isn't the left side supposed to be 2 to the x, instead of x squared, log base 2 would correspond to 2 raised to so.e exponent?

  • @ProfessorDaveExplains

    @ProfessorDaveExplains

    6 жыл бұрын

    ah, technically yes! i guess it's ok because i was just speaking generally and i do the actual derivation properly later, but thanks for catching that!

  • @angelisvegan5826

    @angelisvegan5826

    3 жыл бұрын

    Hey nishant!! A quick question for you too .. How on earth could x rest next to log base 2.. even when x is the exponent.. Cuz exponents aren't supposed to sit next to log base 2...that's the place for "result".... or am I missing something.. Like .. Log base 2 of 8 = 3.. And 8 is but result of 2^3.. but what they're doing is placing exponent in place of the "result"..

  • @thatomofolo452
    @thatomofolo4528 ай бұрын

    Great 👍👍😃

  • @generaltheory560
    @generaltheory5604 жыл бұрын

    How can log be root over

  • @basilrex4105
    @basilrex41055 жыл бұрын

    Prof Dave's tutorial is as clear as a crystal. It is as if David is showing me how to overcome Goliath who is confronting me disguised as Math. Even anencephalous Maxine Waters will be able to understand the Prof.

  • @enzoqueijao

    @enzoqueijao

    4 жыл бұрын

    Thanks for sharing

  • @tGoldenPhoenix
    @tGoldenPhoenix2 жыл бұрын

    Done.

  • @humzahkhalid1886
    @humzahkhalid18865 жыл бұрын

    Is 2:52 right? Should y=b^x be logb(y)= x

  • @insane7493

    @insane7493

    3 жыл бұрын

    yes it is f(x)=b^x then f of inverse of x is log base b of x he is just using y instead of function notation

  • @ericard4165
    @ericard41656 жыл бұрын

    And what's the difference between root and log? Just expressing differently?

  • @ProfessorDaveExplains

    @ProfessorDaveExplains

    6 жыл бұрын

    totally different operations!

  • @rachaelrathore3458
    @rachaelrathore34584 жыл бұрын

    For log x to the base 4 = 1/2, why isn't x = +-2?

  • @ridmicmeena4123

    @ridmicmeena4123

    Жыл бұрын

    Same doubt

  • @abhaypawar7433

    @abhaypawar7433

    9 ай бұрын

    negative numbers arent continuous

  • @felixzeng997
    @felixzeng9973 жыл бұрын

    hi dave i am confused about something you mentioned in 2:58, why couldnt the base be a negative number ? is anything wrong with log -3 (- 1/27)= -3 ? because -3 ^ -3 is - 1/27, isnt it ? or am i missing something ?

  • @saveearth7907

    @saveearth7907

    3 жыл бұрын

    And as you know, unless we're getting into imaginary numbers, we can't deal with a negative number underneath a square root. ... So in summary, because we only allow the log's base to be a positive number not equal to 1, that means the argument of the logarithm can only be a positive number.

  • @felixzeng997

    @felixzeng997

    3 жыл бұрын

    @@saveearth7907 many thanks

  • @saveearth7907

    @saveearth7907

    3 жыл бұрын

    @@felixzeng997 no..thank you..

  • @truesanatani2892

    @truesanatani2892

    3 жыл бұрын

    @@saveearth7907 you know what.. there could be a problem like yours ..but the makers of logarithm did not allow log base or the argument to be negative..

  • @techhelper99

    @techhelper99

    Жыл бұрын

    @@truesanatani2892 @save earth are you both Twins♊!!

  • @kbailkeri
    @kbailkeri4 жыл бұрын

    Yaaay i finished the comprehension in like 10 seconds

  • @jaineilsart1528
    @jaineilsart1528 Жыл бұрын

    Mistake correction : square root of x squared is the absolute value of x. Time marker : 0:41

  • @angelisvegan5826
    @angelisvegan58263 жыл бұрын

    How's that .. 2^x = log2x.. I mean... x wasn't supposed to be there.. Look at this.. 2^3= 8.. and we write it as log base 2 of 8 = 3.. I ain't getting it.. The problem is log base 2 of x.. x is the problem.. x should be outside the equal sign.....

  • @techhelper99

    @techhelper99

    Жыл бұрын

    Log2^x is not equal to 2^x....you are getting it wrong from here itself...

  • @littleretroship6403
    @littleretroship64032 жыл бұрын

    Oh I thought logarithms, exponents and roots were like a three way inverse operations

  • @slowfern
    @slowfern Жыл бұрын

    2:22 can anyone explain please

  • @slowfern

    @slowfern

    Жыл бұрын

    nvm got it

  • @mattitoolu5051
    @mattitoolu50513 жыл бұрын

    Always update me

  • @reasatprottoy7488
    @reasatprottoy74884 жыл бұрын

    4:00 why not -3?

  • @primeprime1047

    @primeprime1047

    4 жыл бұрын

    You're right! We can say x=+/-3 too

  • @jurilynperez111

    @jurilynperez111

    3 жыл бұрын

    b must be positive and not equal to 1

  • @xxxhristopher
    @xxxhristopher8 ай бұрын

    Once again thank you Jesus of sciences. 🎉

  • @aselim20.
    @aselim20.2 жыл бұрын

    I watched it but I didn’t take notes.