Fancier logarithm expressions | Logarithms | Algebra II | Khan Academy

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Examples of logarithms that evaluate to fractional and negative values.
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Опубликовано:

19 дек 2012

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Комментарии : 103

@rogerdotlee 11 лет назад

BLISTERING FARTBUCKET! After almost FIFTY YEARS I've found someone that can actually explain the difference between x^1/y vs x^-y without leaving me wondering if they were doing this just to taunt me! Thank you, Mr. Academy, for finally, after all these years, proving to me that Algebra was NOT designed to make me think that the world was out to make me look stupid. I've got a firm grasp on trig, my geometry is passable, and Calculus makes sense. But this is a first for Algebra. Thank you.

@SarahTheAwesomeLaCroix 10 лет назад

Wow. That escalated quickly.

@lars9310 8 лет назад

+Sarah «The Awesome» LaCroix Haha.

@madblazer8401 6 лет назад

Hahahha :D

@micosstar 24 дня назад

hehehe [:

@jorgerivera6703 9 лет назад

You are better than my teacher

@connorhowitt9164 6 лет назад

agreed

@spongeycraftstudios4371 4 года назад

same

@rogerdotlee 11 лет назад

Indeed it is. My biggest problem was always involving powers, fractions of powers, powers of fractions, inverse powers of fractional inversions, and the meteorological inversions that hover over San Francisco all the time.

@PurpleNoodles 7 лет назад

I feel so smart for understanding all of this xD

@ampleman602 3 года назад

IKR, I did the last one with complete ease, mine came in as 1/-3, but Mr Khan here wrote -1/3, I got scared for a second then my idiot self realised that its the same thing.

@water6133 3 года назад

@@ampleman602 lol

@Gh0StSecurity 11 лет назад

dear mr.khan can u add more problems of integral calculus please? as diff. calculus? I love that problems :D make me feel so confident about my skills thank you

@THE16THPHANTOM 11 лет назад

Weird, i like math more and more as time goes by, mostly because there is a lot stuff in my line of work that keep me coming to this channel and be amazed and say wow its that easy, after spending hours being useless to my colleagues.

@BarunVishwakarma8888 9 лет назад

Sir ji great "I hope u understand "

@projjalm 3 года назад

I'm starting to enjoy these videos as much Sal does.

@carlii435 7 лет назад

while listening all I'm hearing is Joe Swanson from family guy, hard to concentrate lol

@The_Noblesse 6 лет назад

Oh maaahh...goossshhhh..... I'm dyin

@ironmaiden265 8 лет назад

you are awesome. I like the way you make it easy for us to understand.thanks a lot

@byronjones3579 6 лет назад

your a great teacher yea I did enjoy this video loads amazing

@julielemus55 4 года назад

Dude you speak my truth ♥️

@purva_vj 8 лет назад

you are so damn awesome.... love your teaching... thnxx sir ;)

@EngineeringRevised 11 лет назад

Big-O Complexity is one great example of usage

@mehreenayub6831 9 лет назад

What about the properties which allow you to conclude that log baseaxa=1 or common log10=1 or lne=1

@bigstuff52 7 лет назад

Khannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn... great intuitive way to teach this...

@jayasreepatil8960 3 года назад

So understandable

@maalpajara4301 6 лет назад

nice!

@lexiesmiski 4 года назад

THANK YOU SO MUCH

@Quizibo 11 лет назад

Hey Mr. Khan. Do some finance videos on Benjamin Graham and analyze his formulas.

@toutankhamonskiller 11 лет назад

please make a video about the usefulness of logarithms

@ibrahimhcaglayan 11 лет назад

Try making a graph of a parameter whose values vary between 100,000 and 0.0001! That is when you need logarithms. Also, you hear in logarithms, you smell in logarithms, your hair and fingernails grow in logarithms, etc etc... Life is based on logarithms!

@Seattle206723 11 лет назад

Thanks Sal, Been a while since Ive visited, but once again thank you.

@luxfries1524 2 года назад

How on has it been now

@kimsssss 2 года назад

What job are you at that uses algebra?

@Seattle206723 2 года назад

@@kimsssss I have a client that's has a older father that has . This this this and this wrong with his body. I have to supply a 2 RN's that will work 12 hr shifts 7 days a week. I have a demand of $50 hr for each + OT. How much do I charge my Client to cover all expenses and make a profit (X)? I use it all the time. In fact most people do and they just don't know it.

@heinthantsin4330 5 лет назад

I have a test tommorow thanks

@harshranjan5655 4 года назад

1million view but only 1.2 k like. I can,t believe this.

@lamo867 9 лет назад

I understand just about everything in this video, except for the equations that inquired the negative variable, which is basically half of the lesson... (*Face Palm*) None the less, I still learned something from this lesson, and I greatly appreciate the teachings. I go to what some may call a, "special school", and the teachers think I basically am retarded so they won't let me even try to grasp the more difficult levels of math, such as Calculus... :c #TheStruggleIsReal ...

@lars9310 8 лет назад

+lamo867 haha. dont let anyone tell you that you're dumb. I think the majority of our potential IQ lies in dedication and mindset, not how fast we can learn. :-)

@supdenfoosukka 11 лет назад

integrals of 1 over a function to the -1

@dlynn101 6 лет назад

I'm, having a devil of a time finding examples of problems such as "log base 1.5 of 2.3"

@yolandamiller1541 9 лет назад

can this be done in the TI-84 Plus calculator???

@pointman6778 8 лет назад

Yes

@davids1700 10 лет назад

I enjoy all your explanation. Very good!!! Do u explain Primitives also 4 instance?

@KingTv. 4 года назад

I don't think he is going to answer you.

@robertpotapenko2648 2 года назад

@@KingTv. me too

@absarachowdhury7441 6 лет назад

How do u do this sum? 1+2lg x =lg(11x-3)

@omsrisairamtraders9 4 года назад

Cool

@stav200139 11 лет назад

you so smart

@LeetCodeSimplified 3 года назад

1.1 million views, only 89 comments? My guess, a lot of people must be watching this outside of youtube, embedded.

@M4rtingale 11 лет назад

It's time for some Yule log!

@blake1662 11 лет назад

Nice vid - first viewer first comment

@TheRafelito19 10 лет назад

is there somthing more advanced ? for expample dealing with ln and E

@qwaszxerdfcvvcfdrexzsawq3470 7 лет назад

Rafael Santana if you go to actual Kahn academy then they have a few programs there on e and ln

@oyudie2745 4 года назад

Its not actually more complicated its just e is always the base

@PotatoBoiOfficial 3 года назад

4:20 noice

@environ.global 2 года назад

How can I solve 2x log 5 + log 4 = log 8/25 - log 2 I found -2 as the answer

@lukemavericknilo3228 7 лет назад

what if the base and its exponent has the same number how can you solve that??

@firebloom02 7 лет назад

If you have a logarithm that looks like this: log(base2)2, the answer to this problem would be 1. If the base and its exponent and the exponent are the same exact number, the answer should always be 1

@raanoooshh9296 4 года назад

@@firebloom02 correct

@methasawijayasuriya6472 3 года назад

Sal why is the mantissa positive always?!

@bodrulahmed858 7 лет назад

Salman Amin Khan now I know you are Bangladeshi. we are proud of you !

@tamaht.7581 6 лет назад

My brain is trying to make sense of this 😓

@jimverdalupan9510 Год назад

@Threetri333 6 лет назад

Why didn't I have these videos 11-12 years ago?

@flowinori00 7 лет назад

Too fast bruh😂

@alonsopereyra8482 7 лет назад

If someone could help me that would be great: X^-1/3=1/2

@vishaljain4915 7 лет назад

i think you have the answer by now but anyway: x^-1/3 = 1/x^1/3 which is basically 1/cube root of x now we know 1 / cbrt(x) = 1 / 2 we can flip both sides by cross multiplying and get cbrt of x = 2 then to get x we just cube both sides to get ride of the cube root on x and we end up with x = 2^3 which is 8.

@raviaditya9142 5 лет назад

Anyone in 2019

@PhrozenTiger 11 лет назад

Now.. take log(2) of -8 ... >=)

@mikel1888 4 года назад

0-100, REAL QUICK

@chrisarrow 3 года назад

1:25 but why?

@johnsongeorge3268 6 лет назад

I aint enjoyed 4:15 ;)

@michaeltao81 11 лет назад

I don't get this??

@intellexual9097 10 лет назад

Thanks for the lesson! -cue Iggy Azalea's song "Fancy"-

@deadprofile5983 9 лет назад

i have a question why 1/3? Explain why someone plz.

@nilskiisler3032 8 лет назад

+Giovanni Fuentes I can't understand that neither, 8`1/3 is 2/2/3. Or am i calculating something wrong.

@racheldellegatto7382 8 лет назад

8 is a larger number than 2, so you would have to use a fraction in order to find the x of 8. If this were the other way around and we were trying to find the x of 2, it would be 3 because 2•2•2= 8. So the answer would be 2^3=8. But as I said, since 8 is bigger than 2, it would be 8^1/3=2.

@YongkangJR 8 лет назад

+Rachel Dellegatto but 8^1/3=2/2/3, not 2, 8^1/4 is 2 though, did he mean to write power 1/4 instead?

@YongkangJR 8 лет назад

+Yong Kang I found an answer to a question similar to mine on the khan academy website: "Incorrect. There is a difference between ^ and *. You are thinking of 8*1/4, which is 2. The ^ indicates the exponent. This uses multiplication, but is not multiplication. Normally you're used to seeing ^2, or squared. This would mean you repeat the number 2 times and then multiply, so 8*8 = 64. Does this only works when you see the whole numbers? NO! The fraction 1/2 is the inverse of 2 (or 2/1). Therefore the operation is the inverse, so instead of squared, we need square root. For example 9^1/2= 3. Now for the 1/3. If it was 3/1, you would say cubed. Therefore since we have the inverse fraction, we instead need the cubed root. This means what number multiplied by itself 3 times results in the number 8? This answer is 2. 2*2*2=4*2=8. Therefore 8^1/3=2." But i still don't get it, what is the difference between ^ and *?

@094s9 8 лет назад

log8 of 2 = x. 8^x = 2. Change the bases so that they are equal. 8 = 2^3 2^3x = 2^1 Solve for x. 3x= 1 Divide both sides by 3 to isolate x. x= 1/3.

@ufufu001 10 лет назад

confusing as fuck

@IshanTheAwesome 11 лет назад

Negative logs can't be calculated!

@deadprofile5983 9 лет назад

nvm

@charity4613 5 лет назад

public education sucks

@Carlisle412 11 лет назад

I think it was meant as a joke.

@karensanchez4708 6 лет назад

i understand a lot better but his voice madd anoying bruh.

@jsf3669 6 лет назад

bruhhh... "Fancier"..............

@ewerybody 5 лет назад

1:23 eeeeeekk! Wait a minute! "Well if 2 to the 3rd power is 8. 8 to the 1/3rd power is 2!" Why is that so?! Probably I need to see stuff about exponents? Because for me that aint obvious! 😐

@chaaruruuu4587 5 лет назад

yea you need to understand exponents bc logarithms are kinda like the inverse or reverse of exponents or exponential equations

@oyudie2745 4 года назад

Its like your going backwards like imagine if the 1/3 dosen't exist and look at only the 3 now what number to the power of 3 = 8 well that would be 2

@vevenaneathna 11 лет назад

thats the joke...

@dramaqueen9475 7 лет назад

this video was SO not helpful. u didnt tell us how to solve anything. all u did was get straigh to the answer with any problem solving.

@ibitoyetoyin6018 6 лет назад

He didn’t solve them because he had solved several similar examples in the videos before this.

@reinaldodepedro 6 лет назад

To understand this video, try learning first properties of exponents, then with negative fractional exponents. Second try learning properties of roots, then learn square and cubic roots. Third learn properties of logarithms. Success.

@Jazoopi 5 лет назад

thats how logs work

@ryanperez8179 2 года назад

For all have sinned, and come short of the glory of God; Romans 3:23 Jesus lives Jesus Christ is Lord Jesus loves you repent You're a sinner in need of a Savior