Trig: Solving Equations 1

[mohendraamatya]

hey how does cosine go with the variable x????? help pls

[dragias0013]

Your are awesome man

[0Singularity0]

I used to get this, but then I took an arrow in the knee.

[phobak]

beautiful!

[poyanator]

are people studying these in Uni???

I'm in grade 11 and I have this as final year exam...

[baderocks2]

@poyanator even im in grade 11, and my math teacher told us that the things we are currently doing used to be what the teacher used to study in university.

[poyanator]

@baderocks2 my god.. we should be given so much more credit for even being able to fathom some of this stuff!

[baderocks2]

@poyanator yeah but each generation will study more difficult things than us.

[bladeere14]

@poyanator yes we are. economics here

[lairdstreet]

thank you ! really cleared things up ! :)

[UltimateSAB]

thank you!

[hoseinqadam]

Cool I have a blue to his shirt.

[plague566]

I would like to thank you. This is my review for my trig test tomorrow and I feel a lot more confident.

[psychedelicbluesdiva]

OMG I LOVE this bloke. 4 hours of lecture couldn't do what he did in 7 minutes.

[xStanley360]

holy shit. i get it.

[jetnation24]

can you solve a problem for me ?

[Tsukumaropro1995]

Ông ý nói mình chẳng hiểu cái gì cả!

[dlfite10b]

here is a simple way to remember all the reference angles of all the theta

just remember the sin theta

0 degree - o

30 degree - 1/2

45 degree - 1/root of 2

60 degree - root of 3/2

90 degree -  1 The cos of theta will be the opposite of sin theta i.e 0 degree - 1, 30 = root of 3/2, 45 =1/root of 2 ,60 = 1/2 ,90 - 0

now divide sin theta by cos theta and you will get tan theta

i.e= 0/1=0 , 1/2 / root 3 / 2 = 1/root 3, 1/ root 2/ 1/root 2=1, root 3 /2/ 1/2=root3, 1/0=not defined

[Nukefuzion]

@dlfite10b WOW O_O

I thought of this exact way to remember it too :D!

[SuzakuHayasora]

Very helpful! Thank you very much!

[tjwelement94]

look at those eyebrows. damn



[AfroWorld95]

hes the voice of saw...

[JeWlZ4eVa143]

My teacher wants everything in radians, not degrees. Its remembering the radians on the unit circle that always confuses me

[ishowyouapple]

THESE ARE THE TEACHERS WE NEED IN AMERICA!!!!!!! FIRE ALL THE CRAP ONES WHO WANT YOU TO FAIL. THIS GUY ACTUALLY WANTS TO HELP YOU UNDERSTAND MATH

[dinkydodgem93]

THANKYOU FOR BEING SO CLEAR haha, i hate when people are vague lol

[nicklasekegren]

this teacher reminds me of my maths teacher, mr waters

[aquaristic]

9 people failed trig =D

[083Abhi]

can u prove

sec A (1-sin A) (sec A+ tan A)= 1

by solving right hand side

[Gazzawey]

@083Abhi i think u need to multiply them the simplify it u will be able to prove it

[NavB00]

@083Abhi Haha very funny.. you would solve the left side because its more complex

[NorthernFrights]

Very clear thank you

[pinkpunk1290]

You are awesome... Thank you so much

[omogaju]

I think the answer to the last equation was -1. ; -5+2=3cos theta

[BorealNeal]

pointless trig strikes back lol

[ADFOOL]

ITS QUADRANTS I AND IV NOT I AND III FOR THE FIRST PROBLEM

[Generalvaldez]

@ADFOOL Cosine is only positive in I and IV remember the mnemonic device ALL (I) (S)TUDENTS(sine)(II) (T)ake (Tangent)(III) (C)alculus(Cosine)(IV)

[ADFOOL]

ITS QUADRANTS I AND IV NOT I AND III

[Furyes626]

You are an amazing teacher! You made understanding math so much easier for me in the matter of minutes. Please continue what you do because you are great at it. I am really thankful!

[emilyromo]

Wow! I'm actually learning...this guy is better than my college professor...

[Czoot]

Treat that expression! Treat it!!!

[super1range]

isnt #1 wrong? isnt sqroot /2 60 degrees?

[dotZodiac]

@super1range He had root three over two, that's a 30, 60, 90 degree triangle. Since the opposite side is 1, you know that the interior angle is 30.

[NumeralNerd]

thank toy very much!

[S2DAHZ1]

how do you get the reference angle 0=30???? i need to know the anwser asap like right now ;) help please

[JuTimberlake]

@S2DAHZ1 in the calculator, press cos^-1 and then the value, here it's square root of 3 over 2, and then enter (=), and it'll give u the ref angel

[vnessaxox]

@JuTimberlake that does not work... it just says error:domain when i press enter

[xloveisallahoax]

I WISH YOU WERE MY TEACHER IN REAL LIFE

[webmastertool]

@xloveisallahoax He is, watch the videos :)

[cheyennemcnizzle]

you, my good man, are the reason I'm not failing my trig class :D

[TyylerC93]

you make math easy on my brain

[rodrigito1978]

Great stuff! Thanks!

[Laura1123xox]

Thank you! :)

[GamingOutpost]

how is this going to help me in life

[Killuminatismd]

@GamingOutpost it wont. but you'll feel special for knowing it.

[6NAV9]

You sir, are a good man

[Phearix]

thanks alot this helped me alot

[CreativeImpulse]

I know this is besides the point (thanks for this video :D) but man, you should be Santa Claus for christmas~ I can imagine your voice going "ho ho ho" and being all jolly :)

[woodyb707]

Love all you teachers who take the time to do this stuff. Seeing from multiple demonstrations makes it almost impossible to not ace these classes. Thank you



[TheOneAfro1]

THANK YOU OLD MAN!

I wish you were my teacher

[ringoisacandyapple]

this makes so much sence thankyou!

[choppy7272]

that makes sense

[choppy7272]

" that makes sense "

[johnolazabal]

this really helped...thanks brother

[technofr3ak100]

fuck this unimportant horseshit ill take my B and be happy

[K3inMitl3id]

@technofr3ak100 dude trig is what makes the graphics in your video games

[technofr3ak100]

@K3inMitl3id but im not the one making them :DDD but i understand it now so its all good lol

[Wxue89]

This was incredibly useful. Thanks so much for the excellent explanation.

[willhelm87miles]

you're not far behind patrickJMT lol. keep up the good work!

[Sorrow707]

someone give us a hand...

5 cos^2 x = 3(1+sin x).... it needs to be rearranged into 5 sin^2 x + 3sinx-2=0

[Diemedes]

@Sorrow707

Rather simple. Remember the fundamental identity (sinx)^2+(cosx)^2=1. It should be easy after you use that one.

[sajabz2007]

And people thought I was smart ...

[Avatar230594]

Sir you helped me to possibly pass an exam

[demondudekv]

Its beautiful ='D

[BCbaseball90]

Wohoo! i finally figured this crap out. memorize the 30 60 90 and the 45 degree triangles and the unit circle and this will become really easy.

[thenkpa33]

hey! thanks this really helpful its help me a lot

i'm terrible in math speacial graph

[AVPWarlsBack]

You make trig. really fun :D

[AVPWarlsBack]

im confused. doesn't all cosine values lie at quadrant I and II, whereas all the sine values lie at quadrant I and IV?

[Copwatcher123]

Thank you sir,it makes alot of sense.

[kieferslover1949]

you are awesome!

[ilove2shredtheRGZ]

He looks like DR Brown out of Back to the future

[rtdaly]

LOL Math

[JustAddChemicalX]

shaaaaaat uppp!!

[chocoyatte]

At 4:38 or so, if you listen carefully, he says Quadrant 3 while pointing to Quadrant 2. He repeated this mistake with Quadrant 4 (he said Quadrant 3 instead of Quadrant 4 at 1:51). This is his mistake, right? It's a bit confusing... I'm already so confused. Thank you for your math help, your other videos have helped me a lot!

[ARSENALTHEEDIBLE1234]

Brilliant video, really really helped me. Im in England and there are barely any videos I can find that use the graph and answers in degrees, most American ones are in radians; really helped me though! thanks

[mixolidianmode]

this bullshit is not on the asvab

[quisolider]

@mixolidianmode did your recruiter tell you it was? all mine told me was that it was basic algebra and arithmetic hope you had a good score bro

[mixolidianmode]

@quisolider he told me the same thing, i was just commenting, i haven't taken it yet i will take it this summer and i'm going for the marines.

[quisolider]

@mixolidianmode oh well good luck bro i thought the hardest part was the mechanical part of the test, i even took auto in hs but you have to know quite a bit for that part

[NationalPro]

i wish it was in radians

[nenadpocev]

excellent explanation...thank you for the videos..

[jamelmonk]

can cos0 go wit y

[Soljacr7]

i wish i take it that simply!

[misszarina22]

awesome!I adore you!

[Willafurd]

I want you.

[CXVIII]

I want you as my math teacher...

[jwm239]

...one has to make the connection

between sqrt(3)/2 and the 30-degree

reference angle. Many trig tables,

even smaller ones, show simplified

radicals for 30, 45, and 60 degrees

for sin, cos, tan theta.

[Breno06]

Why cant all teachers be as gud as explaining maths as him! =)

Nice 1!

[fireforce7]

awesome teacher. dont know him in person, but i've been using him for 2 years on youtube when i need a refresher. thanks for the help stranger! =)

[ovazquez08]

thank you for taking time to do this! your the best

[mustard286]

8th grade, algebra 1 honors, and i get this!

[STEFANkLooTCh]

not a big deal, but he keeps saying Quadrant III in the second problem, when he is using Quadrant II (4:40)

[ronnash1341]

this man is a god LOL

[TheDoors931]

If you find an answer to that you tell me where people are really going to need this in the real world

[mglsotto]

ugh, architecture? civil engineering? heard of those? =))

[edgars911]

wtf?!?!? :D okay i am only in 9th grade but WTF!?!??! is that? :D where does people use that... ?!?!

[hellod0ggy]

thanks! you the man!

[XStreetKingSX]

wow very teaching!! awesome!

[ricordeon]

BAOINAM!!!!

[rys5227]

what's BAOINAM???

[noneactive]

Just amazing. If I had had him teaching me from the beginning I would not have failed my maths exam.

[theykickme]

.tnx!.

.nice explanation! x)

[gps456]

THANK YOU

[Blueknightex]

Nice presentation. The part that I keep on getting lost is when you draw these lines graphs.

[FoxhoundEmployee]

At 4:43 I think he meant the reference angles for quadrants one and two, not one and three.

[Laynep123]

For sure

[SPOOKSTR]

my brain hurts......

[Blueknightex]

You need to get yourself a graphic calculator to soothe that brainache! ;)

[SPOOKSTR]

If this guy was my math teacher at school...id be a brain surgen now. First job would be working on my own grey matter...i think it's busted.

[kogaxinuyasha]

im starting trig this year so i can refer to this for help

[polos505]

totally understood. thank you.

[vball16rocks]

okay i have to say i have a trig final in 2 days and this helped me SO MUCH. thank you!!!

[corym152]

i wish i was as happy to be doing math as you are

[Soljacr7]

@corym152 hehe

[t0myuri]

i like his polo.

[killapokerpro]

massive

[AIB2K7]

thanks

[arjohnson12]

big help

[chazillah]

I want you as my teacher. Why aren't my profs like you?

Thank you x 1 000

[bigysmls]

whats the tan of sqrt3/3

[wutangforeverbws]

anyone wanna help me....5cos^2 (theta) - 2.5 = 0

then i got to cos theta = square root of one half..which is 45 degrees using the inverse function. so i now have my reference angle...the range is 0<theta<360..... my problem is that the teacher wants 4 different answers but i only got two ...theta equals 45 and 315 since it can only be positive in quadrant 1 and 4....please help me????did i do something wrong?

[RalenSanis]

When you solve a trigonometric equation you must :

- Solve it in Radian not Degree

- Solve it within the range give ( ex : [0;Pi[ )

So after you solved you equation you have something like that :

x = PI / 2 + 2*k*Pi or x = - Pi/2 + 2*k*Pi ( Where k is a relative integer )

After that you must Find the solutions that fits in the range ( [0;Pi[ ) so you must find the coresponding valors of k.

Here the solutions are { Pi / 2 ; 3 * Pi / 2 }

Sorry for my english I am french I hope I helped you ^^

[knifex3]

lol you mean quadrants one and four in 1.52 :P

[FFTGVG]

Thank you. you are an awesome teacher!!!

[athenianboy]

sorry to make this little correction but the solution for the second problem was written correctly on the board but you called quadrant II quadrant III when you said it. However this is a detail. I really like the simplicity of your prresentation. It is very clear.

[chicken11001]

i love math

[Koldness99]

god bless you good sir

[johntallen2]

what?

[RODYBASHA]

U r a GR8 MAN

[raydiobabe]

now, i need a physics version of this channel.

[TanyaTD]

wth - what theta hell? guess I've been out of school too long..or I shoulda partied a little less

[herlequinstar]

you are so very helpful, ty

[zestCC]

Thankyou, so so much

[subtenko]

wtf, i take trig...but wtf is this!? either its too early in the year or teachers dont go over the same things

[ringo692]

this is trig for a circle not triangles

you take this in grade 12

[RipPhilOdonnell]

its fEta not fAta

[MADLmaan]

its actually theta.

[SELGX]

great

[AndyITALY07]

ALL STUDENTS TAKE CALCULUS

[619kammy]

An easier way to memorize the unit cicle:

In the first quadrant its all positive. So if you get a positive answer like sinx=1/2 then one of the answers are 30 degrees or pi/6. The second quadrant is 180-x so to find the second solution its 180-30=150. In the third quadrant its 180+X and in the fourth 360-X. If the equation is on cosx then the answer will be on the first and fourth quadrant. If uts negative it will be on second and third.

[jbizzle700000]

sometimes he mixes up quadrant numbers when he says it but he always points to the right one lol. his math is always right though

[polak3015]

i've seen many of your videos and every time i watch them, i understand it. you are probably the coolest math teacher THANKS!

[moha9]

thank you so much i get it now

[thomas242007]

WTF!! i only understand basic algebra how in the world do you memorize all this stuff

[junkster101]

i dont understand the second problem help.

[kurtismg]

he said sine is positive in quadrants 1 and 3 instead of 1 and 2 around 4:40

[ydultm]

its only 1 and 2. i guess he made a mistake.

[Palestinian16]

Actaully he didn't make a mistake. It is positive in quadrant 1, and 4. In my classroom we use the system CAST

We first draw the cartesian plane and then place the letter C in quadrant 4, then A in quadrant 1, S in quadrant 2, and T in quadrant 3.

By doing that we remember that in quadrant 4 only cosine and it's reciprocals are positive, thats what the C is for.

Then the A for quadrant 1 means sine, cosine, and tan and their reciprocals are all positive.

[Palestinian16]

Also in quadrant 2 sine and it's reciprocals are positive only, and in quadrant 3 tan and it's reciprocals are positive only

[flyingpig319]

Gosh, this is so helpful and clear!!

Thanks SO much for another amazing video!

[denverspurple104]

VERY HELPFUL i have a good teacher too but i am an intimidated student.. soo this is a GREAT way for me to learn trig especially since i like to use the internet =]

[tpingt]

thank you! this is so helpful because i have a test on this tommorow!

[genericvideo1]

Wow I wish you were my teacher! thanks for the vids!

[AntoRoberts]

i hate memorising sine values :p

[Chitownboy1023]

cool

[donk4y]

quadrants 1 and 4... not 1 and 3, as he said mistakingly at 02:00

[danieldraco2000]

the room is really dark. why?!!

[bobolshevik]

use radians more.

[alexhmmr]

This stuff is soooooo simple.....

[Blopartyhut]

genius

[throwbakman]

how do you know that the reference point is 30 degrees when costheta=square route of3/2

[MathTV]

You have to memorize the exact values for sine, cosine, and tangent of 30, 45, and 60 degrees. That way you know that cosine, 30 degrees, and sq rt 3/2 all go together.

[KimKimmyyy]

@throwbakman Look it up on the unit circle. Look at this video: watch?v=cIVpemcoAlY&feature=ch­annel