Lec 7 | MIT 18.06 Linear Algebra, Spring 2005

[SunnyAudiegk409]

soso ich bin blond

[thebigfootme]

excellent!!!

[shinyralle]

at 26:13 I dont get how he can switch column 2 and column 3 to get the identity matrix in the first block of [ I F] ? You cant chage the order of pivot columns just like that ? PLEASE answer this for me someone! 1love

[scotchandsoda123]

@shinyralle all he wants is, that you get a better view for that what he wants you to see. that why he writes it that way

[jojoejoe]

@shinyralle

When you switch the columns of R matrix, you need to switch rows of x vector to make sure it matches original linear equations.

For example,

R11(x1) + R12(x2) = 0

R21(x1) + R12(x2) = 0

in Matrix form,

|R11 R12||x1| equals |R12 R11||x2|

|R21 R22||x2| |R22 R21||x1|

[akhil089]

thanks professor strang

[freakiest421]

linear combination of just two special vector will produce only 2D vector space. How do you know that's the complete solution?

[RadekLudva]

@freakiest421 "there is one special vector for every free variable"

[kotofu]

i just got a rather low grade in my class, wish i spent more time watching his videos...

[Jazzynidhi]

Awesome video :)

[13Septem13]

I found it more interesting and time saving for me to watch these lectures on 2x speed.

[pelemanov]

@13Septem13 How do you play the video at double speed?

[13Septem13]

@pelemanov You should enable htnl5 player: youtube com/html5

it has speed option

[raymedina1990]

Brilliant professor. Bravo really! bravo

[pedroissler]

Actually the part in which he explains the "special" stuff around 30 and it's relations to nullspace could be cut short in favor of the last part, which is somewhat more interesting..

[pedroissler]

I don't love his overly intuitive way of seeing things. I mean it's nice and everything but god do we need formalization here.

[FernandoBatista89]

@pedroissler if you want formalization read a book of Linear Algebra. Kostrikin, for example.

[pedroissler]

@FernandoBatista89 thanks pal

[FernandoBatista89]

@pedroissler no problem. :D

[pedroissler]

HINT: minute 29 when he's "explaining" the R = [I F] thing try to reorganize the A matrix from the beginning in a different way so as to leave the matrix in the format that he describes. The example he gives hasn't been configured that way and that's like a mistake because he kind of jumped from particular to general (actually in a more didatic/less intuitive book you'll have R being called as an echelon matrix reduced by lines)..

[pedroissler]

in this lesson the guy's not so bright

[MrYomantanepali]

great lecture... awesome video... thank you for posting it....

[MrYomantanepali]

great lecture... awesome video...

[scorpionboy3]

I don´t notice the identity matrix at around @22:00

[jrkirby93]

just hope you remember the minus F on the test.

[hoofhearted1212]

wheres his blue shirt?

[hanzvonkonstanz]

@ Dr. Strang: OUTSTANDING!

[TheRealRslive]

if only he would be my teacher

[raneboy13]

thanks mr. G strang

[GodModePS3]

thank you great teacher!

[EssexPN]

MIT Mathematical courses seem very simple..

I am studying Engineering myself in Belgium.

Here in Belgium,we get a much,much more theoretical courses, you have to know every theory, thought behind it, and proof.

No proofs,No theory,just examples are show here!?

[kwakoras]

@EssexPN same here....I am studying physics in Prague and its much more theoretical...but these videos are wonderful to sort things in my head and to see the other point of view :)

[adame903]

@EssexPN This is just my guess, but I imagine this course is geared towards engineering and science majors at MIT, not math majors. Or at least I hope! Because I goto a small liberal arts college no one has ever heard of, and my linear algebra course was much more rigorous than this. All theory and proofs. No applications. Which I didn't mind. :)

[docfromohio]

Spectacular teaching !!!!

[alquiora]

I hope that there is a single lecture on Block Matrices even a short one will be very helpful.

[oilotnoM]

It's fun pausing the video and trying to figure out how the process ends before he's shown it ...

[0nti]

Kudos to you Mr. Strang, and everyone else involved in these videos.

It's a real pleasure to watch the lectures

[WeiliangZeng]

Nice example.

[Janessass]

Better than any Algebra prof in Germany that i have seen. Thanks a lot.

[amarenpdas1975]

a great prof.. abstract maths can so easily taught .... Its amazing...... Great ..... hats off to u

U should come up with simillar lect in analysis

[ChrisBrewster]

@amarenpdas1975 Analysis SUUUUCKS! Gosh...

[amarenpdas1975]

a great prof.. abstract maths can so easily taught .... Its amazing...... Great ..... hats off to u

U should come up with simillar lect in analysis

[CrittyWitty]

So much better than my prof

[amarenpdas1975]

@CrittyWitty

yaa that why if he could do something......

[CrittyWitty]

@amarenpdas1975

Huh? That's not english

[bearcharge]

indeed, rocked my world! listening to his lecture is a kind of pleasure!

[Kamillascookie]

GREAT! I was a bit confused at first but in the end, he rocked my world as always! Thaaaank you!

[gavilanch]

Awesome, i´m glad I found this videos =D

[scorpionboy3]

@gavilanch I´m glad they were made to be found! MIT rocks, more should follow their example!

[truongvoky012345]

very good