Proof: Law of Sines

[AgentFood01]

SOH CAH TOA = Sex On Hard Concrete Always Hurts The Others Ass

[glendale011192]

oh men thanks for this video it helps me alote ^^

[Saiixx]

hey can you show the other proof using area of triangle? thanks!

[HectorL360]

Some Old Hippy Caught Another Hippy Trippin On Acid.

[shoaibliger95]

and our math teacher taught us ' some people have curly brown hair till primted black'

some people have= sin=perpe/hyp

curly brown hair= cos=base/hypotenuse

till printed black= tan=perp/base

[basketboyyu]

thanks!! just mess out with something with this law...thanks!!!!

[meterotronic]

oh...and your favorite word is aribitrary...i've noticed that

[meterotronic]

does not help my intuition....your a very intelligent showoff.

[juifu]

I need the proof of sine of beta over B equals to sine alpha over A equals sine theta over C "EQUALS TO 2R"? I saw that in some textbooks. thank you

[acerbic42]

Saw you on Colbert, congrats man.

[judo1221]

I wish you were my teacher 

[TonyboyDK]

lmfao daymare XD

[maizygrace]

Thank you - I'm in need of a trig brush up and your concise explanation is just right for me. I always need to understand the derivation of formulas in order to remember them. Your simple explanation is very helpful.

[iwillg4]

Did you know that if you were to inscribe that triangle intonation circle, the law of sines ratio is equal to the diameter?

[daymare10110]

our math teacher taught us "Oscar Has A Hairy Old Ass" Opposite hypotenuse, adjacent hypotenuse, and opposite adjacent. I think I like SOH CAH TOA though

[lpbug]

@daymare10110 u honestly made me lol irl

[ikol12]

@daymare10110 Damn! I wish I had a teacher to teach me about Oscar's hairy old ass!

[TheAby2009]

@daymare10110 true that (Y)

[TheNevikProject]

I have heard that the law of sines does not always work 100% of the time. Do you have a video that gives an example of when it does not work?

[sccr2009]

@TheNevikProject You're right, I've noticed it doesnt work in all triangles, its just hard finding those, or finding a relationship in those where it doesnt work.

[MarkAdul09]

thanks for teaching i have many troubles in math especially in trigo.

[Socksysock]

thans for that but is there not two cases the acute and obtuse case? How do you do the obtuse case?

[BILALRAJEY]

thanx for your teaching



[simon247sa]

Aww mate I am teaching myself A level maths as home studying and you make it soo much easier to understand although this is quite confusing still! Thanks for your vids

[R4Y4NO]

you saved my life there :D

[theneonfire]

This video just put me 2 weeks ahead in my maths class xD

[lexinaut]

Nice job! The Law of Sines proof can take you to a higher trickynometric place. It's definitely NOT the height of absurdity although ALTITUDE is certainly involved. Thanks for a colorful and clear presentation. On a less goofy note, the relationship shown is an interesting one.

[MrComplians2much]

i was so confused when you started but you proof makes so much more sense in the end, this really helps me so much for my class

[PTL0]

you are a legend!

[red115dragon]

@PTL0

now THAT is True!!! ;)

<3 KA

[airheadrox]

i cant tell if ur desi... cuz ur accent is pretty good......are u desi?? i have to know

[hobomnky]

ily

[Moonlightkitteh101]

Thank you so much: you have just saved my math grade!

[mochalucha]

ur a good man

[Underwatercemetary]

Please be my teacher.

[InvisblSkratchPiklz]

Thanks for the video.  I don't understand why you start doing what you are doing at 4:30. Could you respond here and explain a little bit more about what/why you are doing what you are doing at that point? Thanks

[beanstie]

He's dividing both sides by A and B so sin(alpha) and A are together on one side of the equation and sin(beta) and B are together on the other side. A and alpha are like partners, B and beta are like partners. They belong together.

[Phizon442]

he's bringing the equation down to the law of sines as seen, well everywhere you see the law of sines.

[IinstantClassique]

It was good the fact that you explained that the rule could be applied if you drew a perpendicular line from any of the vertices.

Nice simple video!

[AshvinChawla]

fantastic thank you it was very well done :)

[angsusi]

perfect.

[LoneRiver1]

much more elegant than the proof in my textbook, thanks!

[dachu108]

Thank you, I finally know how the equation came to be now :]

[seandavidr]

Could you show how to use the law of sines to solve physics problems involving forces and vectors.

[spudcole319]

Just a question, i may not know much about trigonometry, but what's wrong with using two small right triangles to prove the law of sines? What was inconsistent? Also, how would you prove the law of sines? because i really do wanna learn about trigonometry and to see a different way of proving this would be really helpful.

[Paulorific]

Nothing, using the law is just faster.

[OMGWTFBBQTSTIS]

good... i want to die.

[itzdaviddc]

You could explain something that my Pre-Cal book could not! :D

[MuscularBeaverx]

which one do u have? my book's copyright date is 1954. haha

[digsnkills]

You absolutely rock!!!!

[PenguinJin]

Thank-you Sal. You rock.

[chrian09]

dude please get back to me i have a test tommorrow and i need this. is it opposite and adjacent from the 90 degree angle or the beta.

[ppardee]

Opposite and adjacent are always relative to theta. The 90 degree angle should always be opposite the hypotenuse (I believe)

[ppardee]

More accurately, the opposite and adjacent sides are always relative to the angle you are solving for (or with). The hypotenuse is the longest side of a right triangle.

[cutie87654]

wat program does he use to write with?

[aztips]

Sal the Magnificent!! I will earn an engineering degree with much help from this man!

[SenorBastardo1348]

good job bro

[danieloreto]

At 00:49, the triangle has just one angle without name, and this is going to be gamma. So when you draw the perpendicular line to B you will have the same situation than in the video, rather instead of B and alpha you'll have gamma and A. Good luck! (this post is the following part from the former)

[danieloreto]

Actually, transitivity is not a law, is an axiom, so it CANNOT be proved, its a statement which needs no demonstration, it is simply true. Answering mephatboi, the process for getting sine gamma over C (or sine C/c) is the same, but in this case you are going to draw a perpendicular line to B that passes through beta.

[opinionhead444]

I like your explanation. Whether or not the students know it, you are demonstrating the laws of transtivity because all of your ratios turn out to be real numbers.

[WetheKingsCab2008]

lkjlk

[WetheKingsCab2008]

Thank you so so so much!! I was really struggling with understanding this, now it's extremely clear. Thanks again! :D:D:D

[mykeuser]

Excellent!

I memorised this, its the same:

sin(alpha)/sin(beta) = A/B

[xxhasudin]

this is easy stuff but it would be much easier to explain if you used values

[MrMss4]

How would that aid the proof?

[KhroniclesOfNothing]

defeating the purpose of 'proof'...

[MartianSpore]

@KhroniclesOfNothing I forgot that if there is no need to prove something that there is no reason to know something. Some people actually enjoy math and are interested in these things. Other people, learn better when they can understand why things are.

[mephatboi]

i only wanted to see how u get the third part, sin C/c

but that's the part u skipped!

[APHH2]

Excellent. Thanks again!

[qwertyuiop726]

Cool :)