Vector Projection

[Kirbyjonpwn]

thank you for the flashlight analogy. it really helps understand what im' doing

[Roaddogg666]

Thank you! This made 100 times more sense than my professor

[bscmsc70]

Thank you, you just saved me a lot of time and effort

[rlusher2]

you are the bestttt! thank you!

[PhibeRCoRe]

Thank you so much, this helped me alot!

[reyzmeyz]

Thank you <3

[martyp417]

I dont know why you spend your time filming yourself teaching math, but i appreciate it SO MUCH. I wish I had discovered your videos a long time ago. ... i UNDERSTAND!!!

[SRT262]

LEGEND

[livchristinemusic]

I feel like I'd be doing better in my calc 3 class if I sat and watched these videos all day instead of going to class. :)

[nwleng]

OMAGAH I GET IT!

[metal1616]

This actually does make projections a lot clearer for me now

[sidvelu]

I wanted to know why the projection isnt just initally Vcos(theta), and then we solve for theta using cross product. And then we can just solve for cosine theta, and do scalar multiplication?

[illusionmajik]

Finally. Its beyond memorizing the formula. I don't have to memorize it anymore. I know what's going on and the formula is in knowing what the heck I'm doing! WOO!

[ScorpiaX]

@illusionmajik I know right? My damn teacher was like you GOTTA MEMORIZE teh formulas, so you know what to PLUG in...you don't need to know what these formulas do or w/e just know how to use them.

=.=

versus my physics teacher..you gotta ask the right questions and know what YOU're doing.

[aliadeer]

werent u supposed to multiply the 3 and the 4 to fine the dot product?

[aalibobally333]

i was watching the old guy, but this guy looked cuter

[dhavz07]

i love you! thanks for the clear explanation.

[billtheman80]

Clear explanation--Thanks!

[TWEMS110]

Thank you very much for explaining it well! I'm glad I clicked on your video first

[iloveyouu949]

thank you very much nice teaching method.

[darrenwastestime]

you, sir, just saved my academic career.

[KingofWarlock]

THANK YOU SO MUCH!!

[utubegay1]

good job man, nice explanation

[LancerWon87]

first time someone actually gave me a clear explaination. thx man. good job

[Veo77]

Professor Dangarbo10 can you post several videos on lin alg.? I never understood linear transformation and all that other good stuff back in the days. Skip the matrix part I think I am fine with those.

[brrrrrradical]

Nice work man... Well explained =]

[Guffington]

Why is the unit vector :  u / || u || ??

[Norpom]

Great explanation! Thanks!

[janitarjanitar]

thanks for uploading this. I needed to knock myself outta autopilot and truly understand the formula... and well.. you did all the hard work for me!! appreciate it yo

[archiforever]

u r cute ;) hhaha

[autumnofmyheart]

You are damn handsome!!!!

[tlast2012dude]

good stuff...

[0633767jerishowrulez]

i got 57.53 degrees. ?

[TSP2010]

Very helpful video you saved me a lot of time/ reading/ sleep. thanks for uploading.

[jackh84]

In the diagram he has vector v in blue and vector u in red. He then takes a line down from vector v so that it hits vector u at a right angle, thus forming a right angle triangle. Lets call the point of interception on vector u H, and the point where both vecotrs meet at the origin O. The DISTANCE along vector u from O to H is known as the SCALAR projection of v on u, and the VECTOR that describes that motion (ie the distance O to H plus the direction) is the VECTOR projection of v on u.

[Rcp5589]

this helped a lot, thanks

[Freechips1]

Ahh! I'm so stupid. To get the direction (or length separated into x and y directions) I was:

taking arctan of (XLengthU / YLengthU) to get 'theta'

using projectionlength*cos(theta) and

projectionlength*sin(theta)

[333329753]

why do we have to multiply that by unit vector?

[heavycannon127]

I think it's because u does not lie on the x axis, it has its own direction so multiplying by u's unit vector gives you the proper direction. I'm not sure though i'd also like to hear an explanation for that.

[dangarbo10]

The 1.712 just tells us how long the vector is - it does not give us the direction. A vector has a magnitude and a direction. Since we are finding the projection of v onto u, the vector we are finding is in the direction of u. In fact, it lies on u. Thus multiplying by the unit vector in the direction of u gives us the proper direction.

[kurt44ko]

i thought u use the formula a.b/|b| (b/|b|) but this way works

[dangarbo10]

Well, it is true that you can find the answer using that formula ... but doesn't that just leave you a little empty inside if you don't really understand it?

[kurt44ko]

ya i found ur way more understandable

[JJboy1992]

@dangarbo10 no. I just want to answer the fucking stupid vector question haha

[Raziaar]

Okay... so I'm reading this 3D Math book for game programming and graphics, and it just got to a section on vector projection onto another vector. It was completely cryptic to me.

Taking a look at this video though, things are starting to sink in a little bit, as my first pass with it makes a lot of sense. I'll have to rewatch this several times to burn into my head what is being done and hopefully I can tackle this subject.

All the other vector stuff made sense, not vector projection though.

[tuiss113]

fantastic!