Added: 3 years ago
From: patrickJMT
Views: 65,412
Sort by time | Sort by thread (beta)

Link to this comment:

Share to:
see all

All Comments (189)

Sign In or Sign Up now to post a comment!
  • Great video! I have a test on Tuesday and your videos have been so helpful.

    I'd just like to let you know, though, that this video's not on your website.

    Thanks again!

  • @burnskate2

    3^-n = 1/3^n. As n approaches infinity the denominator gets bigger therefore limit = zero

  • Thank you for your videos! Everything is so clear.

  • Erm.

    @ 5:27

    .... Doesn't 3^(-n) approach 1, not zero?

    Otherwise it would be infinity/0...?

    SIDENOTE:

    Thanks for all the info. Your tank work video has helped me study for my final, the most. I've been a bit iffy on the work problems, before. /Really iffy. >>'

  • i love you! thank you so much. ive been watching your videos all day for my final tomorrow. i think ill pass it because of you! :)

  • I LOVE YOUR TUTORIALS!!!! THANK YOU. I'M SO GONNA ACE MY CAL TEST!!!!!! :DDDDDD

  • We left-handed humans are far superior in mathematics and physics...

  • just started studying this in calc II and your video was very helpful. sound quality was good and you made this topic less frightening!

  • patrick you rock man

  • Question:

    If i have an alternating series [(-1)^n-1]/2^n

    This is negative one raised to the n-1 and all of that divided by 2raised to the n power. Can i use the Root Test for that or should i used the alternating series test better? Is it incorrect if if i use the root test for this?

  • @engineerrob 3^3 is equal to 27

  • Wow! incredible... especially the very last part of the root test!

  • You're my favorite teacher! =D

  • I think the second example has a small error. The denominator has the (3^3)(3^1/n). You say that this becomes 27 as n goes to infinity. I'm pretty sure that it becomes (9)(1) not (9)(3) since 3^0 is 1 not 3. Doesn't matter because the numerator is infinity, but still a comment is warranted.

  • wouldn't the limit for the last one be 1/infinity? which is equal to 0 and its going to give you absolute convergent

  • @js6781535 No, it looks like it will at first glance but the number that is being raised to the n'th power is approaching 1 as n goes to infinity. ie - (1+Very Small Number)^(Very Large Number). As he points out, this is the definition of the number e or approximately 2.718 ...or 2.7 1828 1828 45 90 45 (broken up into the memorization pattern to the 16th significant figure, like anyone would ever do that)... Still absolutely convergent either way, but 1/e was correct.

  • you are my new God!!!!!!

  • good for the soul =)

  • You sir are an angel sent from heaven above. this is a legitamate lifesaver.

  • Dude I think I love you :D

  • Great lesson!

  • You're a life saver

  • @yasthilmaharaj is right. Me and my friends from different colleges all use you to get througth calculus classes. Its great

  • God bless you dude! You have no idea how much these videos have helped me for my cal 2 final. the limit of my appreciation for your work approaches infinity. Great work!

  • 4 people are teachers who suck at teaching and force students like us to youtube calc lessons -__- BTW, huzzah to my AP warriors out there!

  • Thank you!

  • Thank you so much! My calculus teacher put a question in our test that used the (1+1/n) limit for e as a sort of "trick" question.

  • Am I just completely off, or is it plausible ? Thanks, and please point out any errors if so.

  • Here is what I have gotten: The sum of (n^n)/(3^(1+3*n))= the sum of (n^n)/(3*3^(3*n)) which could be looked upon as (1/3)* the sum of (n^n)/(3^(3*n)) which could also = (1/3)* the sum of (n^n)/((3^3)^n) = (1/3) * the sum of (n/27)^n which if you then apply the root test and and take the limit of this sum, you would have (1/3)* the limit as n->+infin. of [(n/27)^n]^(1/n)= 1/3 * lim. as n-> +infin. n/27= 1/81 * lim n-> +infin. of n. If you then apply l'Hopital's rule, you reach a limit of 1/81.

  • just so you know your the man. . .helped me through my calc II class with relative ease. Best vids on the net for sure.

  • Lefty flip forever

    

  • How many people just noticed he was left handed when reading this comment?

  • sergio sanchez can die for all i care

  • i love you.

  • Thank you very much for the videos. i use them a lot!! i always stay up all night every thursday to study for my weekly test on friday and without these videos i would not be doing as well in my calc 1 class last semester or my calc 2 class this semester.

  • Thank you so much for making this easy to understand! Fantastic.

  • Near the end of the video, you said "Well, 1 to the n is just 1", but we are taking the limit when n approaches infinity. Isn't 1 to the infinity an indeterminate form?

  • thanks man...

  • sorry, but why did you multiply top and bottom by 1/n? i was doing your problem and i felt legit because i was following the right steps, but instead of multiplying top and bottom by 1/n, i just distributed the n power and got 1 as my limit :(

    care to explain that 1/n thing?

  • I started writing my root symbols like yours. :)

  • very clear explanations !!! I FINALLY GOT THIS!! thank u. I am really appreciated.!!

  • You rock, man. Better teacher than my Calculus professor. And I go to a major university too! =O

  • @armidylano44 well, i used to bore people at a major university as well, so maybe it is all the same

  • @patrickJMT

    Hey, I noticed you're from Austin. I'm actually at UT right now =)

    Anyway, thanks again. King of youtube math, you are.

  • @armidylano44 ha - give me a big high five if you see me on campus or at cafe medici later!

  • @patrickJMT ur a TA?

  • @remirap no, i am long done with school.

  • @patrickJMT i mentioned the same thing on one of your other videos also, i think the reason why people think it is boring in a classroom is because computer are just fun, or some kind of drug that emits out of our computers, lol

  • @patrickJMT No, it's different. Watch Salman Khan's video on Ted. There's a huge difference between listening to someone talk to you and then expect you to understand, vs being pre-recorded so you can stop, pause rewind or choose another person to listen to. We teach math like it's 1799 in this country, and it's friggin retarded.

  • @Raxarax i was being a bit ' tongue in cheek ' with that comment

  • @patrickJMT Ya, I know, but I wanted to vent to someone...

  • dude i haven't even reached at this level of math yet , and im just sitting here and watching it....idky but who knows maybe it will help me out in the future

  • at 6 minutes, isn't it supposed to be 0 times 27? why does the bottom equal to 27? Shouldn't it be infinity over zero? Sorry, confused!

  • @christalwang it's 3^0, not 0. 3^0 equals 1, so the 1x27 = 27

  • @christalwang i was wondering the same thing... i am now scrolling through pages of comments to see if this was addressed..

  • You are awesome. But aside from your teachings, I like your voice, the fact that you're left handed, and that you love Math as well. But now it's time for Diff Eq.. I must leave you.. Thank you for the videos to brush up on my series!

  • @BlueColourPencils awww, thanks! go texas!

  • thank you so much for being there i have been watching you videos for the whole day today about this topic..........they are very much easy to understand..thank you again!!

  • @vjbhatt96 i hope i have not bored you to death yet ; )

  • @patrickJMT No not at all. Your vids just drive me crazy to learn maths whole day long!

  • @vjbhatt96 ha, i find that amazing : )

  • @patrickJMT i like it when you go into the conceptual depths but at the same time keeping maths enjoyable, i feel really grateful to you., you just inspire me.....i like "improper integrals" in your video series very much :-)

  • thank you so much for being there i have been watching you videos for the whole day today about this topic..........they are very much easy to understand..thank you again!!

  • these videos are very much helpful i have been watching sequence and series topic for almost 8 hrs with small intervals and practicing problems in between ....i hope i will do well in exams

    thank you so much ....people like you should always be there ....!!

  • you need to learn how to write a sigma lol!

  • Thank you very much for your sharing ~ !!

  • 5:48 infinity/0 not infinity/27

  • Your videos are very helpful. You are very clear and give helpful tips. Thank you very much!

  • why is is 1\e as n goes to infinity why u dont make it one and anypower to 1 is 1...

  • how can i succed to all my future math courses as u said do we have to hard working or we have to born with a math worm.....

  • At 5:39, doesn't the plug and chug just give infinity/0, not infinity/27? But infinity/0 is not indeterminate anyway, so it doesn't matter?

  • swear to God man, if I ever get a degree and a decent job, I am making a LARGE contribution to your cause! THANK YOU!

  • I noticed you bend the cap on your marker, haha I do that too!

  • Thank you so much Patrick!! You are truly a noble man. Wish i would do more than jst saying thank you....

    God bless yea.

  • What video do you show the proof of the limit (1+(1/n))^n = e?

  • You are a great help, Patric! :D

  • If 1/n -->0 as n -->infinite, why does it matter what An is if anything to the power 0 is 1?

  • why didn't they teach this in alg 2/college algebra? it would save me all that studying for calc ii.

  • @patrickJMT in example 3, why did u multiply numerator and denominator by 1/n in the second or third step of the problem?

  • @patrickJMT

    Thanks for all your videos!! Its much easier for me to study math when I can pause and rewind the lecture :)

    But I have a question, say I have a sum of (x/n)^n

    what do I do with x?

    at the end I got:

    lim (x/n)

    do I say that it converges for x<n? I coulndn't find examples in the video where there was x as well as n

  • omg, thanks a ton patrick!! i have a maths exam next week, luv ur videos so much

  • You've got a flair for teaching, man! Try getting on a seminar circuit. Do you have your Masters?

  • @BornAtTheBar yep, got a masters

  • wow i feel dumb lol

  • Dude you are the best man. I appreciate the time and effort you put into your videos. 

  • Brilliant stuff. As an aspiring physicist at the university of Oslo, in Norway, these videos have given me a much needed pre-exam repetition. Keep up your excellent work.

  • Hey man you`re so great ......I doubt if you`ve ever heared of Jordan in the middle east ....but you know,you`ve helped me and bunch of my friends with our calculus I&II here in Jordan so keep up the great work &

    God bless You:D

  • @5ANASHEEROA do you mean michael jordan? was he in the middle east?

  • @patrickJMT eeeeehhh, Jordan is a place >>

  • @corpsemunger pretty sure it was a joke man

  • @corpsemunger yes......i live in west jordan utah

  • @patrickJMT lol... I love your sense of humor

  • @patrickJMT lol

  • @patrickJMT Actually Jordan is a place in the Middle East. FYI: "The small Kingdom of Jordan occupies a strategic location in the Middle East. This arid and ancient land (of biblical fame) has witnessed centuries of conquests and invading armies. " Search More On Google if interested :)

  • @avik58 pretty sure it was sarcasm man.

  • @patrickJMT no theres a place called jordan located in the middle east. You are making such a huge a positive feedback

  • @beansombrero lol patrick was just kidding...

  • @patrickJMT Lol.idk if that was a joke. But he meant the country Jordan.

  • Thank you very much, all these videos Make my life so easy!

  • bro, thanks a lot for your videos.

    i'm a math tutor in my spare time, and i very much respect your concise and confident teaching methods.

    this series of videos helped me refresh on power series for my (ultra-brutal) complex analysis class!

  • couldn't focus on studying, kept watching youtube videos, now I have found the perfect combination.  Youtube+studying=progress

  • Geez you make it much easier to understand than my professor...great stuff!!

  • Fantastic!!!

  • i would just like to thank you. you have no idea how much you have helped me. thank you so much i really appreciate it. if only all calculus profs were like you.

  • YOU ROCK. I have a calc test this upcoming monday

  • why at the end of the second example does the last step he got: inf/(0X27) and he said it turns into =inf??

    Isn't this incorrect?

    I solved the problem by taking the third from the series itself and then you won't get that 0 at the bottom.

    can n e one clarify?

  • @showABCshow he did it right. anything over infinity is zero, therefore one over infinity is zero therefor 3 ^ 0 = 1 so the denom is equal to 27

  • @spacebird413

    wow.. my bad I just saw that 0 there and I thought he meant 3^(1/n)= 0, but he meant 3^0.

    Thanks.

  • Awesome video dude, this helped me a ton thank you

  • 5 star

  • definitely wish u were my calc teacher instead of the ones i have -they all suck

  • you are amazing

  • Very helpful. Much better than my cal II teacher who assumes we know everything.

  • @vdubnthehouse seriously -.-

  • thanks alot for the videos. i just wanna know what kind of whiteboard or white sheet of papers you writng those things on? i like it i wanna know the name so i can get it for myself. does anybody know the answer? help pls!

  • the name of what he is using is called printer paper and permanent markers.....

  • Well you probably get bored of hearing it, but you've saved yet another student. Thanks for these videos. You're doing something great for students everywhere.

  • thanks man, you absolutely rock!!!!

  • Patrick how do you do it? I wanted to make some Linear Algebra vids but my voice became shaky, lips and tongue became stiff, nose started spasming (like stage fright), needless to say I didn't post those videos. How on earth do you keep your voice so calm?

  • glad you like them all : )

    i figured that if they suck, i would just delete them. most people seem to like them though : )

    and honestly, i forget half of this stuff, so i make them for 'future me' - the one that has forgotten and re-watches old me (newer me?), so i have to be nice and soothing to my future self : )

  • that's a good strategy, works out for all of us

  • "most people seem to like them though" No No Patrick. Everybody LOVES them. You are a great man. Thousands of students around the world are more grateful than you know. Thank you for the time and effort you put into these videos. They have saved the lives of many students.

  • For the last example on this video it is easier to use L'Hopitals on that limit by taking the ln of the limit instead of having to memorize that that limit equals e. You can show why it equals e.

  • your videos are brilliant patrick, just brilliant :)

    by the way, i wanted to ask if n-th term theorem could be used on your 3rd example here.

  • Patrick. If I ever see you, I will kiss u on the mouth. This stuff is absolute greek and then you come in and put it all in layman's terms and voila, it's like magic.  My brain has been having the "AHA" moment all day. Thank you sooooo very much dude. You make me wanna bake you cookies. That's saying something.

  • ahahahhaahah - that is awesome!

    kisses + cookies = a good day

  • @lorebetty "i will kiss u on the mouth" bwahaha.. but seriously i probably would too

  • So basically, series with (a sub n)^n, you can treat "a sub n" as your common ratio (r), and your (a) as 1 so, if r < 1, then it's convergent. Just right out of your first couple of videos.

    RIght?

  • OMG I agree with Inferfire........it is plain scary that I understand all your root test/ratio test stuff, I have my final tomorrow and before these videos I thought I was screwed because i have absolutely NO idea what my prof is babbling about....I wanna seriously thank you so much!!!

  • Comment removed

  • is it scary that i understand this video??

  • probably not

  • in Europe this method is more oftenly reffered as Cauchy root test :)

  • this is the stuff u need for college. so technically you flame yourself with tht

  • The sad part is we learned this in school!

  • what do you call when you multiply num and denom by 1/n, and one more thing patrick... why the denom ...(1+1/n)^n equals e?... it shouldnt be 1? thank you in advance

  • (1+1/n)^n Is a notable limit witch equals e, look for it... and the 1/n multiply by num and denom is just a simplification, it doesn't affect the equation as you are using it in the top and the bottom..

  • this is cool xD

    thanks

  • i just randomly clicked this video, and thank you for making my brain blow up.

  • me too  xD

  • great lesson. Just one thing....series, in general, have many techniques and laws..

    1) how do I know which technique to use when i see a formula?

    2) what determines if a limit or series is convergent and divergent? when 0 is it always convergent? Please answer. Thank you

  • Those are fantastic questions. I would love to see a video just to have those answered. Is there a possibility of having this done?

  • How do i know tht i hv 2 use the root test 4 these kinda question

  • Normally you can use both ratio and root for these questions. it best to use root test for questions like (n)^n

  • WTH!?!?!?

  • you lost me at "in this video".

  • heck! you lost me when i saw the second paper!

  • Hahahahahaha! I thought it was some drawing lesson! :P

  • u lost me too

  • i love you

  • In the last example, the limit of n to inifity of 1^n is not just 1, but infinity. Over e, the series diverges by the root test.

    Awsome job, I love watching your videos!

  • 1^(any power) is 1, so I think he was correct

  • @21chuck  1^infinity =/= 1

  • i was just wondering if it was possible to use L'hospitals rule to work out hte limits here ? would it b appropriate?

  • i'm pretty shocked at the last one how it turns into e. hmm... if i remember correctly, that's the compounding interst formula isn't it?

    ahh i hate e, its so mysterious.. one day i'll have to sit and ponder :)

  • well, 'e' is used in the continuous compounding formula.

    and dont go hatin' on poor ole ' e ', it just wants to be useful like all the other numbers!

  • I've never loved a man this much. No homo.

  • dude ur a lifesaver. Thank you for all this. You make so much easier

  • OMG! thank you soooo much for posting this...watching this is way better than reading off a paper : )

  • is this also called as the Root rule comparison test?

  • You are awesome!

  • i think you need to flip your fraction (n+1)/n

  • i have a question on the second problem when u got to lim of (n/n+1)^n..isnt that e..y did u do all that other stuff like mult top and bottem by 1/x to get the 1/e?

  • Great videos, they are really helping my preps for the exams! By the way, at 5.45 you say that 0*27=27, not that it matters, the answer will still be the same.

  • ops, thanks!

    i did that in another video too : )

    i am making sure everyone is paying attention!

  • Comment removed

  • Actually, isn't 3^0 = 1?

    So this would be 1 * 27 = 27?

    Which is correct.

  • If you look back to his solution you will see that (3^0)*(3^3)=27 and that is the same as yours.

  • It was not a mistake...it is 3^(1/n) as n->infinity so it would be 3^0 which is 1.

    It doesnt matter anyway...it was just to make it clear.

    Thanks listening to me :)

  • Why did you multiply the top and bottom by (1/n)?

    I know it lead to the (1/e) but... what made you do that?

  • well, it is basically knowing that the n/(n+1) is the flip of (n+1)/n; that raised to a power of n has something to do with 'e'! i am seen that limit so many times now, that i just recognize it. so to answer your question, what made me think to do that is: experience!

    sometimes one has to be shown what to do a few times before it sticks!

  • at 8:35 you said that the limit of 1^n as n approaches infinity is 1!!

    i thought 1^infinity was indeterminate!

  • 1 to any real number power is 1.

    the problem is if you have a function of the form [f(x)]^[g(x)] and f(x) is APPROACHING 1 (but not necessarily equal to 1).

    limit notation is not very good; the standard notation is to use equality, when in reality it is just 'getting close' to that number (in most cases). eventually, one figures this out and just learns to deal with it : )

  • Thank you Sir.

  • thanks so much

  • no problem

  • you're the best it gets!