Introduction to Logarithms

[iD7my]

can't we raise 2 to the power of minus infinity to get zero?

[thesharkshit]

I laughed out loud at the LogaRhythms story

[theazertysimo]

Thank you! Thank you! And thank you!!!!!!

[KittyForTheWin]

Thank you! I have to write a provincial math exam tomorrow, had no idea what logs were about O-O

[maria17954]

When am I going to actually apply this shit in real life. Fuckin shiet. Who fuckin came up with this shiet. I bet the person that invented Logarithm was on all the drugs ever invented,

[450015508]

@maria17954 You'll learn about it indepth in calculus in college (which I doubt you'll be going to based on that ignorant comment of yours)

[HydroFilicManiacBear]

@maria17954 Hehe......... wow. Never is really the answer, based on your estimated IQ. But if you plan on becoming an intelligent person focused on pushing the boundaries of science and math.

[yonmoore]

I'm watching this video with the hanna sound track by the chemical brothers playing in the background and it's making it exponentially more interesting.

[12121994]

i am soo subscribing to your channel

[jimbojones091]

My sister is failing trig and all she keeps saying is o these logarithms and this shit is easy as hell.

[EvermoreDrive]

I've got a pre-calc midterm in about two hours; you, kind sir, just royally save my buttocks with these logarithms. Thank you.

[84gti]

Awesome! -- well aside from the LogaRhythm insight.... lol

[stephenjones102]

30+ years since dealing with logs and trying to re-learn it. YOU made it so simple. Thanks!

[CriticalCritics2011]

your coughs scare the shit out of me, otherwise good job, my math teacher can't even teach

[stephenjones102]

@CriticalCritics2011 Wow, sorry to hear about your teacher........aren't these videos lifesavers?

[mrb8808]

@Georgiatracy are you really just learning this in college. Wow

[blashblash123]

Thank you! :)

[olatoffen1]

You're better than my teacher!

[GeorgiaTracey]

I think this guy just saved my college career

[rameshknair39]

thank you!

[rameshknair39]

this is

[Brandisofthesand]

convenient * sorry xD

[Brandisofthesand]

This is amazing, and its so convientnant. Coz by the time I get home and get situated I forget how my math class went, and then my notes only has bits and pieces. So in class " OH, I can remember that!" This is so easy..." gets home "WTF?!?!" |:O

[hekje12345]

This is crazy, I don't get it.

3+?=6? To get ?, we substract! It makes sense!

5*?=10 To get ?, we devide! It makes sense too!

?^2=25 To get ?, we use the square root! It makes sense again!

5^?=80 To get ? we...... err..... we log?????

Well..., there everything stops making sense.

[kattikakes]

I love it... logs almost make sense now. thank u

[ryno123321]

I couldn't find any with ln or e :(

[GreenEggism]

your cough at 2:34 scared me

[h0minid25]

the easiest way of defining a logarithm is something completely worthless.

[Akleloki]

@h0minid25 We all say that in our maths class :)

[itsme0anni]

dont worry sal, you always make sense

[handuong53]

I always hope I click and get Sal. He explains it the clearest, in my opinion. And he is enthusiastic while he teaches it, too! It is comedic relief when he goes off on a tangent. I can only imagine what is brewing inside that man's head. Thank you Sal!

[56Thunderstruck]

This manu has saved my ass too many times...this dude is the truth ..my respect

[ReflexiveBeef]

9:26 your grammar is starting to be put into logs lol! Very helpful, thank you.

[C0k3d]

I will most probably fail tomorow's test >_>

[BrantonVideos]

i love you

[Msbbopalula]

I clicked on the first vid I saw on logarithms and I heard your voice and was like "yesssssssss", I always learn something with you.

[svea1995]

thank you so much! my math teacher sucks

[rellom777]

Great!!! its like having a tutor!

[RainbowManification]

I'm never going to get this in time, guess I'm failing my algebra 2 trimester final :/

[isawthemlive]

i fucking hate logs. 

[romash8]

Логарифмы для детей! В Беларуси их изучают в 10 классе

[occupiedusername]

@romash8 So you think White Russian is superior? I think your dear leader should go shit himself.

[dlarkaigh]

Log (-1) to the base 10 is 0+pi(i)



[zinalovesuju]

why cant i just raise 2 to 0 to get 0?

[safarifirefoxchrome]

@zinalovesuju Because any number raised to 0 always equals 1. 

[Leeonard89]

@zinalovesuju

it's a mathematical rule. you, in the real numbers world, can't use the number to 0 power and having a 0 result

[happybro1]

Ok heres a question: What is 8^pi=x in logarithmic form? The answer was log(base)pi =x. I thought it was log(base)x=pi.

WTF

[Wikan95]

@happybro1 neither, it's log(base 8)x=pi

[MrJahanzaib97]

Hmm .. You're Right :P

[UberTroll13]

17 people are still working out X

[kevinbuzu]

Super Video man !! thanks for the help :)

[seragreen]

you taught me more in 9 minutes than my math teacher in 2 weeks! i wish our teacher would simply show your videos in class. it would be much more productive..

[luckyvirgo090]

well done !

[wongIgnow]

Thank you!

[TheLoveformankind]

watching

[EarthBornGordo]

Please don't stop making these. You're currently getting me through my pure math 30 course because my teacher is bad. Thank you so much!

[BobTubeStudios]

After I saw this, I googled the natural log of -1. It blew my mind...

[ItaTRAP]

no longer get b prus

[Jzing29]

Thumbs up if you thought "zero!' at 6:15

[karim3343]

RIP STEVE JOBS

[IdiotWithSticks]

Thanks dude! This is much more fun than le math book.

[Morkv0076]

thank you sooo much! :D you just helped me answer my math quiz!

[MTran0708]

not paying attention in school ftw! or maybe just crap teacher ftl...

[Bigflaggedguy]

SO IS HE SAYING EVERYTHING IS EQUALED TO = 3?

[prince1234567899]

@Bigflaggedguy No, it's just a coincidence that all the examples he used equaled to 3.

[Bigflaggedguy]

THIS IS CONFUSING

[ScarredWingz]

my teacher did pure shit at explainin this and wikipedia just hurt........i guess i must do my add maths course on youtube

[Rollich]

But what is the point of logarithms? That should be explained first. Why are they used? What's the point?

[KoushOWNs]

I'm raising my hand but no ones answering... :3

[chapasaurus]

Thanks a lot. Taking the GRE's soon and this really comes in help. Thanks!

[shayan894]

:) i want to be just like salman

[nabhanabuljabl]

GREAT HELP!

[MrAlienpirate]

i was in cabbage maths last year then over christmas holidays i watched this channel now that im back at highschool im top of my mid stream algrbra class. thanks bro you are a top man !

[BobTubeStudios]

I absolutely love the internet. I'm a Sophomore in High School taking Algebra II. I already know the material, so I decided to check out a trig book, then I moved on to preCalc. If it weren't for the internet, I would still be struggling in Algebra! =DDDDDDDD

[rabbifilms]

Zero



[rigoagui]

I bet sal gets tons of college pussy.

[lwrncc]

Why wasn't this around 10 years ago when i needed it! Could have changed my life!

[hcallig]

I am unable to express through a youtube comment how much of are help you are making this video. It saved my sanity.

[CarnaTiges713]

I love you so fucking much!

[XxFightinDirtyxX]

13 people dislike having a good quality instructor teach them about Logarithms.

[quangngy]

What part of a play list is this in?

[missypunkrocker]

hehe.. The Logarhythms...

[a4b3c2d1e0f]

you gotta love the internet :)

[blo141]

wow this makes perfect sense now. my friend from trig class told us about your videos. keep up the good work

[britishaccentsftw]

THANKYOU OMG My teacher is teaching us logarithms and I couldn`t get it at all. It`s not even part of our syllabus and yet she1s giving us quizzes and I always failed. Now our midterm tests are coming up and I just found this video. THANK YOU, I get it now! :D :D Keep making more videos please! :D

[Subaru537]

@jjosephty1 Yes because in grade 12, they expand that knowledge of log into functions. You'll see what I mean when you're in grade 12.

[animemangaluv13]

5:43 i felt so smart for knowin the answer before him!

[animemangaluv13]

beast

[TheLoveformankind]

u r great

[thatgurl123453]

OMG!!!!!!!! MAN thankkkkkkkkk yooooooou!!! I understand this now or atleast better then i did in class . You make it make sense , in class i was like WTF!!! Wut the hell , how'd you get that. Man your a genious ! Thanks Again (: Im definately Subscribing!

[reuben024]

u sir r truely a great teacher thank u sir

[DJBrah]

wow.. i know your a better teacher than mine when you got to the point of

log base 100 1 or wtv and i yell out ZERO!!! as the answer.. you have grabbed my attention better than any other teacher!!!

[TheRuth101]

This was a lot easier then how my professor explained it.

[PkedYou]

You just taught me more in 30 seconds that I learned in an hour of math class. Thank you so much.

[RukifelthCreuz]

I gotta say, i'm disappointed. Khan normally does a good job of describing where these things comes from, but here it's like

"These are logs. When you do this, you get this. That's it."

[EjPwned]

12 people are too stupid to understand logarithms.

[bicnarok]

seems like a daft idea to me, why not just leave the things to the power and save complicating things.

[111Fett]

Whenever I need help on presentations for math topics, you always help me pass

Thanks a million :D

[JpJangz]

wad happened to my pen?!?!? haha

[MrSmf500]

this looks way too easy

[JeziMingo33]

This helped so much. Showing examples is always more helpful to me than just showing formulas. :3 thank you!

[countolaf32]

Thumbs up for having finals tomorrow!

[SkillGuideHQ]

lol "so this equals...Qeustion mark" LOLOLOLOLOL :D i love this dude!

[3fishhooks]

you remind me of cocaine and doo doo stains

[uj26894]

gr8!

[MrDevin666]

FREEEEEDOMM!!!!!!!!!!!

[Silverson12]

videos like this make me think school is purposefully confusing

[vreblinz]

awesome. Now, how come I didn't get this from my teacher explaining it? Doesn't matter, thanks.

[nkakm]

this've been a really great help to me.

I have an exam on this tomorrow, if it wasn't for the video I wouldn't have passed!

thank you so MUCH!!

[FlyWithMe4ever]

you are my hero.

[katiexxsayss]

THANK YOU!! God forbid my teacher tell me what a log is while we are doing a logarithm unit!!

[andrewchinesedragon]

.....WHERE HAVE YOU BEEN ALL MY LIFE? XD

[tnafan20077]

ive been doing these at school for like 3 weeks. and i don't get it. i watch this video for 45 seconds and it makes all the sense in the world. WOO AMERICAN SCHOOL SYSTEM!

[animemangaluv13]

@tnafan20077 hahahaha ! amen!

[alvinogot]

tnx

[kimo2161]

who the ..... who press dislike

[TheLoveformankind]

@kimo2161 u mean who the fuck pressed the dislike button

[kimo2161]

u r the best math taecher eveeeeeeeeeeeeeer any one who agree press like :D

[FashionStatementz]

I was struggling with engineering mathematics chapter 1 basics and this helped me THANKS!

[Sotardie]

I solve things differently from this guy. But thanks :)

[RoMMeL1337ak47]

why isent 2^(-infinety)=0 ? is it for the same reson as x/0 isent infinety? i dont get that ether...

[BloggerMusicMan]

This was really great, and this coming from an arts student who absolutely despised math in high school. I echo everyone else here saying you are a wonderful teacher.

[007abhinavagarwal]

thanx!

keep posting more !!!!

[IsunzaTan]

YOU ARE JUST FUN.. so i learn better

[MsPucca2011]

You are such a natural....I enjoyed all your videos. I have learned more from you than from my professor....keep up the good work!

[TheJudgeSam]

probably bcoz teacher was coughing :P and now they r 11 :P

[dancingkgurl]

YOU ARE SO SO SO SO SO HELPFUL!

thank you sooooooo so much !

[harman5453]

11 ppl still don't understand how to do logs, tsk tsk tsk tsk

[djmopa]

Thanks for posting this video. I am in college and struggle with math and the logs have been stressing me out, this video makes a lot of sense and I like how to you give different examples for each problem. Very helpful!

[varunvaibhav714]

itzzzz jst awsum n gr8.....

[darknecromancer34]

does 2^ (infinity) = 0? just asking, thanks :D, btw thanks

[clarinetmeister]

@darknecromancer34 infinity is not a number but when x gets arbitrarily large, 2^x gets arbitrarily large - 2^x means we are multiplying by 2 over and over, which makes the result bigger

[usuckbad2]

@darknecromancer34 It equals infinity

[fujiismydog]

Thanks heaps mate. Relatively easy stuff once you explained this. Cleared up all my confusion. Appreciate your work

[funkyyoungstuff]

Wow I understood more after watching this than after watching my intermediate algebra teacher's college video lecture. Thanks for this video.



[TheGSB2011]

this stuff is the simple part of logs just wait till you try learning exponential regression

[tenseman08]

@TheGSB2011 hahah lol..its not the worst thing in the world

[spartan171jidman]

hi

[z50king29]

I am becoming a teacher. I will not give a thumbs up until I know why you do not give a general form? I see potential for exploration by self if a general form is given

[clarinetmeister]

@z50king29 Log base a of b = c means that a^c = b.

[MrMaestro14231]

how do solve x to the power of x equals two?

[clarinetmeister]

@MrMaestro14231 this is actually rather complicated to be solved with basic use of logarithms, but the answer is approximately 1.56 (if you are interested, look up the Lambert W function)

[Nkhades]

Thank you thank you thank you....Tilll now i didn understand log and now its kinda fun to do...

[jimmydewberry]

Thank you very much!!!! You are a life saver

[repdogg94]

11 people use negative base powers

[bogidrau676]

thanks alot khan.....im from tonga and im studying in china and i alwayz sucked at maths but with all your videos i feel invincible....lol

[tayyabhassanzahidkmk]

Best math teacher

[145bobby]

93% on Honors Algebra 2 math test due to this and the other videos on logarthims :) thanks. My teachers tests are very hard, but I could understand what to do, just with hard numbers.

[Skytheater]

Thanks I just learned something new!

[evalpeva]

You may actually be the reason I will pass my graduation exams. Thank you!

[MorganIacolucci]

.Kudos to this guy for bein badass

[Hippoman141]

Thanks this helped a lot!

[sayitisntsokthnxbai]

haha, loga RHYTHMS :D

[rjtheweasel555]

imma doa buncha more problems lol

[Skyathaniel]

11 people saw a scooba diver with a happy face at 1:12

[Ace2358]

11 people fucked up their exams

[TheElmuro]

this video makes perfect sense for us but i believe that if math teachers see this video they wont get it because they are so dumb.

[PoliticalJohn]

you're the best math teacher I never had.

[Hudstahh93xoxo]

I'm doing my A level in Maths over in the U.K, and my teacher just makes everything so complicated!! Thank you soo much, you've made this really easy!

Who would have thought Youtube, would be educational?

[shopoholic23]

everything makes sense!!!!! thank you so much!!!

[azavgz]

I can go to MIT!!!

[AlainasAbyss]

I'm not going to lie. You're my hero. I have the most frivolous Algebra 2 teacher so after trying to learn a lesson in class I come home and watch your videos. You've helped so very much. Thank you for caring and thank you for being different and amazing at what you do. :)

[jxcalero]

this is SO much better than how my math teacher explained it to us.

[gizmosachin]

You're awesome.

[CheeseWizify]

Damn MIT! :D

[ion010101]

I've never been able to get past these "introductions" because I don't know what is meant by "logarithm" and "base". I know what I'm meant to memorize, and I can only guess that perhaps base refers to baseball or perhaps math headquarters... It's school learning. Nobody's fault. We're socialized to transmit this way and mistake it for "learning". Read Ivan Illich.

[Elynwen]

Keep in mind, Dollface -- even if you didn't go to MIT, and went to a community college, you could still understand things like this. I think that's part of the point he's putting across... we're often disillusioned by big names and test scores. Maybe what it comes down to is a love of learning, and the natural ability to teach. The world is a better place for people like Professor Khan! Thank you!!

[Npowell01]

@Elynwen

Couldn't have put it better myself. I've personally decided to postpone pursuing an education favor of pursuing knowledge. America's educational system had it's foundations laid in the late 1700s. It's ineffective, irrelevant, and expensive today.

The Internet, if used correctly, can be a better resource than any individual university out there. And more cost-effective to boot!

I set my own schedule, don't have to worry about corrupt teachers, a class that lags behind me... etc.

[snowboard2000n]

@Npowell01 i see your point, and agree in a way... but this day in age you need a piece of paper from an institution saying youve completed their program to have that knowledge be recognized.

[Npowell01]

@snowboard2000n

You only need the piece of paper because the status quo says you need a piece of paper. I don't think that's right.

Now, shall I go the the first route, whereby I "suck it up" and do what I'm told, while perpetuating the existence of a system I disagree with, or shall I go the second route, and see if I can't generate a large income with knowledge alone, proving that having student loan debt when you're 40-something doesn't have to be a universal truth?

Bill gates: dropout.

[ahmadu007]

@Npowell01 Zuckerburg : dropout  even Einstein: dropout!

[mathiex1993]

Thanks

[DarkGuitarKid]

9 minutes of this meant so much more than 1 hour of my teacher

[ekacupaj]

please help me with this one.........i dont know what to do when there is a number in front of log..

log (base 7) X + log (base 7) 2=log (base 7) 8

[gutfood]

@ekacupaj klog(base a)x = log(base a)x^k

[ion010101]

@ekacupaj X times 2 = 8. So X must be 4. That's when yer adding logs, I think. 7^n = X. 7^m = 2. 7^y = 8. You can ADD n and m to get y or you can multiply X and 2 to get 8.

You can watch this happen with easier logs. Log by itself means base 10... so Log 100 + log 100 = log 10000 or 10^2 + 10^2 = 10^4 (2 + 2 = 4) or 100 times 100 = 10000.

Oh, if you must be pedantic and obscurantist, these are "properties" of logarithms. Pardong me, I'm off to play the grand piano...!

[ekacupaj]

@ion010101 wow, thanks alot! :D