Combinations

[tahseen1995]

What playlist is this in? It's so frustrating I don't know how to find out which playlist what video is in..

[muttigangster]

we can say combination is (5 & 3) can be like this ( 5.4.3 )/3!=10 its like the same for permutation p(5,3) = 5.4.3=60 you go down from 5 3 times;)

[Mraloneandsad]

at 6:00 it sounds like hes sayiing fukin f2 ahahaha

[muttigangster]

@Mraloneandsad duuddeeee:)

[samiellaia]

Thanks a lot !

[EmbraceTheThunder]

Soooo...

n choose k?

[fgunton]

he keeps saying permutations this is a combination order doesnt matter

[GenericCoder]

Thanks alot for the logic of these stuff its really useful.

[toplad007]

Thanks for explaining the logic behind these formulas, really enlightening!

[grayshorts]

Another thing that causes confusion is the phrase "locker combination". In math we are told that when we are finding combinations, that order does not matter, but when we need to open a lock, the order of the numbers matter, but it is still called a "locker combination". It should be called a locker Permutation because the order of numbers obviously matters.

[grayshorts]

You would use a permutation when you care about order, like how many different ways can a group of 5 runners come in 1st place, 2nd and 3rd place. You would use Combinations when you DONT care about the order of things because they don't matter. LIke if a teacher hands you 10 questions and she says "Do 6 out of the 10 questions in any order you like" you could figure out how many different combination of questions you could choose from.

[MasterThief1324]

No one taught me this in precalc >=(

[BKA320]

Would it be possible to get exercises at the Khan Academy website for this?

[ch3mawattz]

i still dont understand when to use each of them, like in word problems i always use them backwards :(

[withsuccess]

Confusing :(

[Deathdome9]

@justinchenpwns

Bull shit

[TheWejdin]

Im still confused to hell. What the hell happened to D and E? Gahhh! Why wont this just click! Fucking brain is useless

[StaticShock1100]

Seriously, Khanacademy= WIN

[88TieFighter]

This is very easy to understand.

[justinchenpwns]

we're doing this stuff in 6th grade

[danatelle]

what if the number of seats are not given instead it says in a row, how would you solve that?

[DawnBreaker1100]

Congrats on a featured video :D

[GrimHeaper364]

How many combinations are there of 2 girls and 1 cup?

[xSouLPuriTyx]

this is permulation not combination

[rrenvall]

Why is this guy not the most popular youtube channel ever ?!?!?!

[kitkatsweetie15]

@rrenvall besides nigahgia

[facedown220]

3 people don't know how to combine..^_^

[facedown220]

3 people don't understand it...^_^

[crystalidx]

Why is he using P for combinations? Isn't he suppose to be using C because the answer needs to be divided by the ! of the number on the right of the C?

[myonlynick]

permution-> i care about the order of numbers

combination--> i dont care about the order of numbers.

[myonlynick]

permutation VS combination difference?

example:" there are many combinations to select from but only one permutation will unlock the lock."

correct me if i'm wrong.

[insanezain0]

I DONT GET WHEN YOU USE PERMUTATION VS COMBINATION ???

WHAT TYPE OF QUESTION

[s2xc]

What's the formula of finding how many routes are in 20*20 grid ?

[monkeywatcher]

Can some1 please explain to me why its 5 x 3 x 2 x 1 at 9:22?

[monkeywatcher]

@monkeywatcher Haha.. nvmm he corrected himself at 9:43

[jacquesl22]

@monkeywatcher thats a permutation.. correct me if im wrong

[MrGreylor]

Guys I am not a native enlish speaker and as a result i cannot fully understand the term "Permutations".

-if we have 5C2=5!/2!(5-2)!=120/12=10 Combinations (based on Binomial coefficient)

-if we have 5P2=5!/(5-2)!=120/6=20 Permutations

So can somebody shed some light on my confusion? Thanks :)

[TICOMMECA]

@MrGreylor

permutation is different from combination. permutation is when we care about the order of the object, in combination we do not care. so generally permutations has greater value than combination.

[TICOMMECA]

@MrGreylor

2:51 he explained it there

[MrGreylor]

@TICOMMECA Cheers! Now I really got it. Thanks :)

[expt22]

Does it mean the following:

Number of combinations = (Total number of permutations) / (Number of permutations per combination)

[GMmarine]

This was better than how my Algebra 2 teacher explained it, this provided a much more enjoyable experience. :D

[nerdyyyfool3210]

THANK YOU SO MUCH. you saved my math grade.

[Skies678]

Great video, the book I am from likes to over complicate it, and now I understand it perfectly.

[Skies678]

@Skies678 that was meant to say *the book I am working from* haha

[MrPlender]

It's funny how I enjoy calculus and algebra with no problems and yet I find these permutations and combinations the hardest topics in maths! I have to watch these videos quite a few times before I begin to start grasping them properly.

[LordAlda]

Congrats on trying to compress this topic into 10 mins. I didn't truly wrap my head around the topic until I related this to 3H in 5 flips... where there aren't 3 types of H, just H.

Btw, I watched the binomial video first... and that really confused me. :-P

[GDATERRY]

THANK YOUUUU

[xtremmethod]

The last 3 videos summed up a month of stats and probs courses

[chicainger]

I understand it!

[creampuff274]

hello prof thanks a lot for your vids. ahmm can I ask for your YM so that I can consult you if we have new math problems or lessons pls, its ok if you cant I totally respect your privacy Man.

[Qaboom]

The way I originally thought of it was nCr = nPr / rPr, but that just ends up being nPr / r! anyway.

Great videos!

[jakyastik]

nPr / nPr is 1.. That means nP0. Understood?

[xoxotrish17]

hmm..im confused..if there was a problem,how will i know if i will use permutation or combination?

[8dimensions]

Maybe I'm too late, but I'll reply anyway (maybe that will help other people too): as Sal said, "a combination is a permutation where you don't care about the order".

So, in short, you'll use permutations when order matters and you'll use combinations when it doesn't. :)

[Awzyn8]

you mean when order doesnt matter you use permutations and combinations when it does?

[jakyastik]

Just understand it this way. Permutations is like arrangement. and combination is like making groups from the given data.

[psychodriveskip]

@Awzyn8

no. Order matters is generally considered to mean that you take order into account. You use permutations when you take order into account (that is, B and then A is not the same as A and then B)

[yanomandin]

you must identified the problem,

[DanielKovach]

@xoxotrish17 You gatta know the order of operations ferst

[williamtaylor29]

Yes you are indeed the man.

[martillerita]

I <3 YOUR VIDEOS! Really,helps me so much :) thank!

[dmceye]

thank you, it helped me remember my precalculus stuff.

[dylanVSzach]

interesting