Finding the Determinant of a 4 by 4 Matrix

[mdimarco87]

This seems easier though huh?

[EbayEspyguy]

r u fuckin serious lazy ass bitch

[Hairypottysucks]

yr a lifesaver dude

[pidhalbert]

Perfekt!

[Azazel91]

Very good!

[luclfersangel616]

A real mathematician would choose a column with 4 numbers.

[JamesPatrickMartin]

@luclfersangel616 A real mathematician would get it to upper or lower triangular form and multiply the diagonal ;)

[EnvyProjekt]

Thanks but to make some better videos, you really should do some more challenging examples.

[4kx]

Thanks from Poland! ^^

[Xxrockerchic229xX]

thankss (:

[markyw19]

Excellent! Thank you for helping me understand this! You rock!

[infernoj2]

wtf can this guy explain any worse?

[felimillo]

lazy asshole too many zeroes

[jsowmy]

ok how do i find the cofactors for the elements in the 4by4 matrix?

[Requiem4Kill]

If the sum of entry is 'even' we use +?

[createmy23]

@Requiem4Kill It's (-1) ^ the number.. if the number is odd, like in this case, then -1 to the power of any odd number is still -1 and if the number is even, then -1 to the power of any even number is +1. So you're right. It'd be + . Did that answer ur question?

[milashiv]

why does cramers rule not work on 4 by 4 like why doe we have to break it up

[TheFOIBOS]

amazing...i wish teachers in Greece could teach us in this way...

very simple.....profesorfs teach us in such a scientifical way that nobody understands!

this way it's much easier!

[kosalarox]

thank u so much .. that is what i find ...

[trekstar2114]

@highrollerjm use matlab :P

[TheSidewayschef]

Thank you very much! After watching this, I figured out what I was doing wrong when finding the determinant of this type of matrix. Thanks again!

[turbinder]

THANKS BABY

[juanpgarcia91]

"u might wanna choose the one with most 0's" fukin lazy ass modafukah

[halo92507]

Thank you!!!!

[dandandan330]

dusty example

[xtClown1987]

wow!! thanks man!

[efralopez1]

Looks easy but why did you change the five and the other numbers to a negative?

[kobhi4ev]

The 5 is called the Cofactor.

I won't go into too much detail however, you need to imagine the matrix having a pattern:

+ - + - ...

- + - + ... This pattern corresponds to the sign of the Cofactor which you take out.

+ - + - ... The sign of the cofactor can also be determined by looking at the (row, column) index.

For example, in the video, the 5 he took out was in row 2, column 3.

Quickly do: (-1)^(row + column) = -1 therefore, the Cofactor will have to be multiplied by -1.

[Jop243]

thanks so much

[sakomprod]

thanks so much!

[SerialMonogamistress]

this is a very shabby way...this is also the co factors rule...and its not clear exactly why u changed the 5 to -5....i dont like this way

[Tiduas]

This was a very easy and useful example you showed us, now I finally understand! ^_____^

[karichary5]

You saved My life!!!

[sandmitch1]

Damn this guy! Really?!!!!? A 4x4 matrix where there are FIVE zeros? Anyone could do that. I need to know how to do one with only one zero!

[kobhi4ev]

@sandmitch1 You can do a combination of row reductions and cofactor expansions.

[highrollerjm]

fuck this guy he gives a easy ass determinant with three 0's in it... what do i do when theres no 0's :/

[xikinhoxikinho]

@highrollerjm is easy you just have to do 1 by 1. Is the same process but do it to all 1 row.

[shaheel]

yeh man

@highrollerjm

[shiningyrlife]

@highrollerjm elementary row reduction

[MrVoiceofreason123]

@highrollerjm grin and bear it.

[enquiryplay]

@highrollerjm It doesn't matter. You may choose any column or row. The only reason to choose one with zeros is that its easy to multiply by zero which means less work.

[MrGibbification]

@highrollerjm elementary row operations!

[TheSidewayschef]

@highrollerjm I usually use the column with the smallest numbers. Then break it down from there. But if there is at least one zero in a column, use that one.

[MrHockeysnipeshow]

@highrollerjm

This guy uses a stupid method, put the matrix into RREF (triangular matrix). Then the Det = (main diagonal multipled). Remember to use the rules:

1) interchanging rows multiplys the determinant by -1

2)Multiplying a row results in the determinant being divided by the the same number.(vis versa)

3)Addition and subtraction do not effect the determinant.

3)

[jincontrol]

@highrollerjm lmao

[Peebukas1]

@highrollerjm

You simply have to make some 0's

[circle5566]

@highrollerjm

you'll have " the evaluation is extremely laborious and will not be considered in detail." when you read the text book.

[SpyroBoyEternal]

@highrollerjm The same thing he did, you will just have more to calculate.

[heartachescream]

thank you!

[rottenseed]

blech...this is the barbaric way of doing it...

[THE16THPHANTOM]

at the +3 matrix if you multiply the diagonals you get 24+6=30 , but you got 18. how did you do that , am i missing rule? any one who gets this reply if you can.

[1012298]

@THE16THPHANTOM

you want to subtract the 6

[THE16THPHANTOM]

@1012298 right. i was too stressed out back then, let it be a lesson to all. Don't start learning your math a day before your test.

[neethux]

what if u choose any row rather than a column?

[iLoveEatingPie]

@neethux No difference, as far as I know...

[arthurespiritu16]

what if no column or row has three "zero" elements?

[iLoveEatingPie]

@arthurespiritu16 it doesn't matter, then you just add the smaller determinants of other numbers too. It's just he didn't write anything for the others, as they are equal to 0.

[arthurespiritu16]

@iLoveEatingPie yeah thanks, i missed the concept on how you have to consider the whole row or column for the determinant

[flaggedyou]

is this cramer's rule?

[sanaaH17]

what does 'odd' mean?

[sanaaH17]

@sanaaH17 got it

[naveed03316477347]

If we not have any zero in Matrix then what we should do please tell me



[TheAble2see]

clear, simple, great job

;-)

[M55ikael]

Does anybody know where this lecture is taken from? I´d like to buy more if I can.

[Morglurg]

Very clear! Thanks.

[hentallica]

thank you so much

[st0nedge]

great tutorial

[1991hayla]

WHY IN THE BEGINNING 5 BECAME NEGATIVE?

[IronFace2342]

@1991hayla it is at an uneven spot, 5 was at the second row (2) and third colom (3)

=> 2+3 = 5, this is uneven. So the 5 will become -5

Rule: 5 * (-1)^(colom+row) => if the row+colom is even the -1 will become 1 thus can be left out

[1991hayla]

@IronFace2342

mmm thanks :)

[kai0shin]

@IronFace2342 so it's pure coincidence that A(sub)2,3 was also 5... what if it was 8 or 6 or 7.

do you see what i'm saying. 2+3=5 and that 5 became a -5??? right.

[ddwerner8]

why didn't you multiply 18 by 3 at the end?

[sunny221388]

you have choosen 5 because most of the elements in column third is zero , but if there is no any zeros then what should be choosen?

[BigGame89]

this is a nice chapter

[mxcxsxg]

Very clear. Thanks a lot.

[OohTouchMyTralala]

Thanks! Was lost on this type of problem till this run through!

[WonJinnH]

excellent this finally cleared things up for me thank you!

[gothwal100]

this is a nice chapter

[sam20891]

why is it plus 3 and not negative 3?

[sirfunkington]

@sam20891 it follows a +, -, +, -, +

repeating pattern in the x& y directions

starting from the top left

[chudnadis]

Awesome!! it's easy to follow!

[roeen07]

Hi! Thx for nice video,can du find the Determinant of a 4 x 4 matrix too? thx

[tweakedmofo]

Thank you, that was enlightening.

[dianataurasifrk1]

nice!!! so helpful! my teacher can't teach... but you can!

[PassedMeBy]

hey... mine 4 by 4 dont have any zero.. does that mean i need to do all of it?

[dianataurasifrk1]

well do your rows have 0's??? because then u can pick any column and instead pick a row with 0's.

[TheDynastking]

question. What if there are not as much zeros do you still just pick a number and cross out? Also if it's odd its negative but if it even its positive right? I learned something completely different and very hard (factoring) so this seem nearly unreal to me so let me know.

[huntflex]

thanks! I can't believe why my math book didnt just explain it this simple!

[jimrummy1300]

byron?

[dangerouskokbang]

yesss you da mannn broo

[pmmets07]

thank you so much i was going to fail my test but i had my iphone in class and watching this LOL

[EFun5273]

thnx for your video!! helps a lot on my revision for my mid-term test!!

[DahakaGR8]

Thank you

[dragon21605]

omg @___@ this is awesome man, just saved me on my quiz~

[Zen09]

ty alot

[dan1088352]

You should see the way my math book described it, this makes sense! Thanks a ton!

[vishalug]

thanx for explaining

[redsuns2k8]

wha?? i dont get it [why -5]

[Astralistearis]

YEAHHHHHHHHHHHH!

[sweetspice06]

thank you so much for this video

[dizzinicol]

thankyou!!

[Ventriscosa]

Now it alll makes sense!!

[wackid89]

What if there's huge numbers and no zeros to start with!!!

[carrie20660]

any column will do. but starting with more zeros is easier~

[wackid89]

That's what I mean, it would take forever without the other methods!

[Mizumi17]

I wish teachers would teach like that, AND THEN go into proofs, of why and how it woks. then repeat this easy way... that'd be soooooooooooooooo much easier!!!!!!!

[TheTrueIgorto]

if they're even, the number is positive, not negative

[Qrawzseg]

what happens if they are even?

[1hat4u]

do you do all the rows if there arnt zeros. Also how do you solve a monster 5 by 5 with no zeroes HELP!!!!

[superflex008]

Hey great Job, I also love you ..in a very non-gay way !

[searchadvancedupload]

i love you in a very non-gay way

[paulgregoryl]

i finally get it! thank you

[fragileth1ng]

good!! i didn't hav to replay it to get it. thanks!!

[karst9900]

i think the solution is -295 not -250

[pnoyguitar]

um...0 det times any number is equal to zero. but it's very easy with 0's. What if there are no zeros. Then it goes back to basic. Anyways, good job.

[evfanning]

Ps3 sucks man!

[pnoyguitar]

lol

[guilo123456789]

very nice vid

[nirvan1111111]

gud job thnx

[alireza1989]

really helpful video. Thanx a lot

[fady721]

helped me alot thank u very much

[kal6060]

thanks u

[eneida007]

Good job! It helped me a lot. Thanx.

[kaisellgren]

Very nice!