I had a question in my quiz yesterday that looks almost just like #6 and I couldn't figure it out for the life of me. THANK you for clearing it up for me! Your videos perfectly align to my Calc 3 class!
@melchiortod293 жыл бұрын
My teacher only brings limits where you can't plug it in😂 thank you very much! Well explained!
@beyourself1963 жыл бұрын
your videos help us a lot. thank you from core of my heart
@stnguyen12342 жыл бұрын
Hey im taking Math 2415 right now. These videos are straight to the point and helpful!
@danielrojas39583 жыл бұрын
Nawebona me salvaste el primer parcial mi reina, excelente video, me suscribo
@daddyji374211 ай бұрын
btw you are very wonderful teacher and love from India 🇮🇳
@HamzaAhmed-oq5od4 жыл бұрын
In the last example how do we get a 2r^2 and then the further 1/r in the numerator?
@elmao49272 жыл бұрын
are there rules to the paths you can take? as in can you add constants so that y= x+ 5 for example
@sfxyz37463 жыл бұрын
You are really the best
@ERKBOI4 жыл бұрын
I cannot understand the last example. Can you clarify it a little bit? Where does rsin came from?
@alexandraniedden53374 жыл бұрын
The rsin(theta) is the polar conversion for y (think unit circle). Likewise, rcos(theta) is the polar conversion for x. Hope this helps!
@enriquesoler31503 ай бұрын
I have a question for these types of limits: after I try direct substitution and got an indeterminate form, do I just go straight into proving the limit DNE or first try limit rules first to see if I can get a limit value, and if that fails I prove the limit DNE?
@alexandraniedden53373 ай бұрын
First try limit rules. Ultimately if you get an indeterminate form, the limit most likely doesn't exist, but not always.
@ChefFarisMom38 ай бұрын
I have a question for last questions. Sin theta Ln r applying LHP rule then it will be Cos theta .1/r?
@prriyka3 жыл бұрын
You are incredible!
@isisyasmim6393 жыл бұрын
At 33:18 I'm having a hard time figuring out where that 1/r and -1/2r² came from. Can you clarify, please?
@alexandraniedden53373 жыл бұрын
When you substitute r = 0 into the limit, you end up with infinity / infinity. This is a case where L'Hopital's Rule applies. After that infinity / infinity, I took the derivative with respect to r. The derivative of lnr is 1/r and the derivative of 1/(2r) is (1/2)*-1(r^-2). I hope this helps!
@isisyasmim6393 жыл бұрын
@@alexandraniedden5337 Thank you! Now I get it!
@Salamanca-joro3 ай бұрын
21:10 in this example i made y=0 and i got 1 for y axis and 1 for x axis as well so the limit does exist and it value is 1 right? Or we are supposed to prove that the limit does not exist?
@alexandraniedden53373 ай бұрын
Showing that limits along two paths give the same value does not prove the limit is equal to that value. Oftentimes if we cannot substitute in the point, then the limit does not exist. The task then is to find two paths which give different limits; hence the limit would not exist.
@Salamanca-joro3 ай бұрын
@@alexandraniedden5337 oh yeah I forgot this! Thank you so much
@jkk23-g7c2 жыл бұрын
Great course, thank you very much. I wonder what textbook you are using. Is it the Stewart's Calculus textbook?
@rayalhar Жыл бұрын
Yes
@mukisajoshua20262 жыл бұрын
I love youuuuuuu ❤️❤️❤️❤️ u saved my day
@woldie21273 ай бұрын
great thanks
@ekindinek3 ай бұрын
for the example 6 , 31:09 ; why did you only check the r goes to 0+ but not both 0+ and 0-
@ekindinek3 ай бұрын
i think it may because of lnx does not exist for negative side, but what if it would exist, shouldn't we check both sides?
@alexandraniedden53373 ай бұрын
In polar, we take r to be positive, so we do not need to check 0- because this would be a negative value for r.
@olidialunga85933 жыл бұрын
Did I miss where you ended up explaining "the other trick"
@alexandraniedden53373 жыл бұрын
Can you please give me a timestamp? I'm not sure what you are referring to.
@olidialunga85933 жыл бұрын
@@alexandraniedden5337 16:37, when mentioning the 3 options, option number 3 was 'one other "trick" ', which you had said you'd explain later. I didn't get that trick in the end. Did you mention it in this video?
@alexandraniedden53373 жыл бұрын
@@olidialunga8593 Ah, thank you. The "trick" I was referring to is finding the limit using polar coordinates rather than rectangular. See example #6 for this method.
@olidialunga85933 жыл бұрын
@@alexandraniedden5337 Oh, that makes sense. Thank you!
@jkk23-g7c2 жыл бұрын
I had the same question, so thank you for asking this.
@daddyji374211 ай бұрын
are you teaching from thomas finney calculus mam ?
@hafiziehamdie85022 жыл бұрын
have you covered chapter 14.3? or maybe it is on a separate video?
@punyisasrimuang77824 жыл бұрын
31:25 why y become r sin?
@alexandraniedden53374 жыл бұрын
I converted from rectangular to polar coordinates. For the conversion, x = rcos(theta) and y = rsin(theta). It will be easier to evaluate this limit using polar coordinates rather than rectangular.
@abeimnida Жыл бұрын
I still dont understand why in example we need to consider the line y=x?
@alexandraniedden5337 Жыл бұрын
I'm assuming you're referring to example 2. If so, the line y=x shows us that the limit as (x,y) approaches (0,0) is not the same along every path. I thought to choose y=x because that would give me -x^2 in the numerator, which I could eventually divide out with the denominator (not giving 0 as the previous 2 examples did). We had a feeling the limit would not exist so it was important to find a path where the limit did not = 0.
@user-dx3qg4tn6g4 жыл бұрын
any 14.3 video?
@alexandraniedden53374 жыл бұрын
No, sorry! Here is a video from a colleague covering 14.3 (his says 13.3, but it's 14.3 from the textbook I use - Partial Derivatives): kzbin.info/www/bejne/m4napmZ6oM9ob5Y
@kaneeindall5733 Жыл бұрын
Thank you!
@HamzaAhmed-oq5od4 жыл бұрын
Are you sure the derivative for sinx lnx is correct?
@alexandraniedden53374 жыл бұрын
I am not sure where in the video you are referring, as I do not see an example with sinx lnx. That being said, the correct derivative is: sin(x)/x + ln(x)cos(x).
@Salamanca-joro3 ай бұрын
8:21 you could have just said : Since 0 does not equal -1/2 the limit does not exist at ( 0 , 0 ) right🤨?
@alexandraniedden53373 ай бұрын
Yes, that is the ultimate answer to the problem :)
@mukisajoshua20262 жыл бұрын
Brilliant
@aryankundu4954 Жыл бұрын
16:36
@codingwithelhacen9904 жыл бұрын
21:39 . why did you chose y=x? can you also do limit along x-axis and y-axis?
@alexandraniedden53374 жыл бұрын
For example #4, I first approached the limit along the y-axis (which is x=0) - this was part a. I got the limit to be 1. If I had chosen to approach the limit along the x-axis (y=0), I would have also gotten 1. I could certainly have chosen to approach along the x-axis rather than the y-axis. Doing both isn't helpful (see next paragraph). In the case where a limit does not exist (which was likely the case here because we couldn't immediately substitute (0,0)), we need to find 2 differing limits. That's why I chosen y=x, because approaching along this path produces a limit of 0 (part b). The two differing values in parts a and b show that the limit does not exist.
@abdullahalgarea32604 жыл бұрын
@@alexandraniedden5337 Hello I saw some videos and I thing you are the best you tuber I have seen and I want to ask you if you have section 14.3
@abdullahalgarea32604 жыл бұрын
and I want to say to you keep going
@alexandraniedden53374 жыл бұрын
@@abdullahalgarea3260 I don't, but this is a video on partial derivatives (14.3) from a colleague of mine: kzbin.info/www/bejne/m4napmZ6oM9ob5Y Hope this helps!
@benjaminandrew79402 жыл бұрын
@@alexandraniedden5337 Thank you so much
@govindc7690 Жыл бұрын
Can you please upload the notes?
@benjaminandrew79402 жыл бұрын
is there a 14.3??
@benjaminandrew79402 жыл бұрын
I saw your reply to another person and see that you do not
@abhijitkashyap33383 жыл бұрын
Madam please solve the following f(x, y) = {1/x^2+y^2 (x, y) not eq (0, 0) 0 (x, y) = (0, 0)