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Sarg338


Joined: 07 Feb 2008 Posts: 5143
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Posted: Thu Sep 22, 2011 2:09 am Post subject: |
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conlan22 wrote: | Sarg338 wrote: | Grrr, this is just not clicking with me. Doing Trig. Substitutions, and even a simple problem is tripping me up.
Quote: | Integrate: Sqrt(4-x^2) |
x = 2tan(Theta) dx = 2sec^2 (Theta) dTheta
And after that, I just don't know what to do...
I think I may change my Major to a BA in CS instead of a BS, since I'm not getting anything in Calc II (Bombed my first test :/) |
trig sub is one of the hardest things to get in calc II, but that being said, you just take the test on it and then pretty much never see it again in your life. I am a math major and the only class trig sub showed up is Calc II. I'm sure you will be fine in the long run. jw what math classes do you have to take for the BS? |
Quote: | 201. Analytics and Calculus I (5)
251. Analytics and Calculus II (5)
260. Discrete Mathematical Structures (3)
313. Linear Algebra (3)
318. Probability (3) |
Eh, I've already decided to drop Calc II and go the BA route. I've tried (Hence why I waited close to 6 weeks to decided to drop it) and it's just not clicking. Oh well.
A BA in BS requires 18 hours in a minor, and I will probably just do a math minor, since I only need 3 more hours I believe. _________________
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THABEAST721


Joined: 26 Dec 2007 Posts: 2000
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Posted: Thu Sep 22, 2011 3:43 am Post subject: |
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We are finally getting into actual calculus in my multivariable calc class. We just touched limits of functions of more than one variable, and it's pretty interesting. Hopefully it doesn't lose its appeal due to being incredibly difficult though. _________________
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bclare

Joined: 21 Jun 2008 Posts: 6048 Location: Boston
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Posted: Thu Sep 22, 2011 3:54 am Post subject: |
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THABEAST721 wrote: | We are finally getting into actual calculus in my multivariable calc class. We just touched limits of functions of more than one variable, and it's pretty interesting. Hopefully it doesn't lose its appeal due to being incredibly difficult though. |
Honestly, if you don't mind vectors and if you can do Calc I/II stuff, then multivariable calc isn't bad at all. The hardest part probably is being able to visualize things, which isn't always strictly necessary but can help a hell of a lot. _________________
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THABEAST721


Joined: 26 Dec 2007 Posts: 2000
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Posted: Thu Sep 22, 2011 5:22 am Post subject: |
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Yeah visualizing really helps a lot. I impressed my teacher by solving a problem of finding the line that goes through a certain point and is perpendicular to a given line in 3-space with a clever solution he didn't think of. I'm not trying to brag or anything, but I just thought that was really freakin' sweet. I feel like I have the vectors and visualization down, so I guess I will have some fun in this class. _________________
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THABEAST721


Joined: 26 Dec 2007 Posts: 2000
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Posted: Thu Nov 03, 2011 11:22 pm Post subject: |
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Would it be possible for anyone to explain this solution to me? I don't really understand what they are talking about.
With a binary operation being something like addition, subtraction, multiplication, division, modulo, or something custom. If someone could give me an explanation that would be great. Maybe you could explain it if the only 4 operations were addition, subtraction, multiplication, and division, and extend it to a more general sense or something like that? _________________
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bclare

Joined: 21 Jun 2008 Posts: 6048 Location: Boston
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Posted: Fri Nov 04, 2011 1:41 am Post subject: |
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A binary operation is a mapping from S x S to S (where x here means cross)
I'm going to call my operation *, because my keyboard doesn't have a button for (plus sign inside a circle)
We're implicitly only concerned with closed operations, where a*b = x and as long as a and b are in S, so is the product/sum/whatever x.
This is equivalent to saying (a,b)-> x, the ordered pair (a,b) maps to x.
This is very general, so we aren't assuming that * is symmetric/commutative.
Basically what is being said is that however big the set S is, we can make a *-table that'll be n rows by n columns, for n^2 total entries. Each of those entries could be any of the elements from n. (n^2) choices to make, n options each, so it's n^(n^2).
Here's a small example. Say we take the set S = {0,1}. Standard addition isn't even a binary operation on this set (1+1=2 is not in S) but multiplication is, and it looks like this
(assume this is a table with rows and columns both labeled 0 and then 1)
0 0
0 1
But I could define another operation on S like this
a*b = 1 for all a,b in S
1 1
1 1
or another operation
a*b = 0 for all a,b in S
0 0
0 0
Or I could give operations which don't even have a single general rule, just a direction for each particular case:
0*0 = 0
0*1 = 1
1*0 = 0
1*1 = 1
0 1
0 1
Etc. I hope it's clear that there are 2^4 possible tables that can be made here, and the general case is just with n not necessarily equal to 2
edit note: We're also talking about distinct operations of course. _________________
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slfan68


Joined: 30 Oct 2007 Posts: 656 Location: Pink Hill, NC
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Posted: Fri Nov 04, 2011 2:50 am Post subject: |
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So I'm in Math 122 here at my University, which is basically Calculus I and is also a M Tu W Th F course. However, I have quite possibly the worst teacher ever to teach at all. I took Calculus in high school last year, so I have a pretty good idea of how things work. However, she does not explain things like theorems at all. She writes them on the board and then proceeds to just working out problems. AND THEN, when she's working out problems on the board, she will, multiple times per class, make very stupid mistakes yet she continues to work the problems. Sometimes we catch her mistakes as soon as she makes them, but often if she makes a mistake on something she is just teaching us, there's no way we can know that she's making a mistake. AND THEN (it gets more cool), on tests we are given some of the most ridiculous problems she can think of. Problems that, instead of testing that we know the Calculus concepts, instead end up testing how well we can do extensive amounts of Algebra. And we aren't allowed to use calculators of any kind. The combination of ridiculous problems with an incapable teacher make this the biggest joke of a class I've ever seen. However, I need to somehow pull my grade up to at least a B, or I'm going to risk losing my scholarship. So frustrating
EDIT: I forgot to mention the teacher is on academic probation from the University for having consistently terrible pass/fail rates in her classes. Just one more thing to make me love college -.- _________________
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THABEAST721


Joined: 26 Dec 2007 Posts: 2000
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Posted: Fri Nov 04, 2011 3:03 am Post subject: |
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Ok I think I understand it a bit better now. I will be relearning this stuff next semester in an actual math class, so I will probably understand it a lot better then. Learning math in a computer science class just doesn't achieve much. We are getting into combinatorics, but the teacher doesn't really teach anything; we are just expected to already know a lot about them, and apply them to algorithms. Right now, the math class I am taking (other than calculus) is an intro to mathematics class, and we have just finished learning the basics of sets. So this stupid discrete math course for computer science is ahead of that class, and the teacher is not all that great; he's one of those guys who hates teaching but works at the university for a good opportunity for research.
But anyway, I think I understand it better now, so thanks for that. _________________
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GlassDragon


Joined: 24 May 2008 Posts: 1122
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Posted: Fri Nov 04, 2011 3:27 am Post subject: |
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Combinatorics and set theory are common introductory topics in math but they can be intuitively very difficult. You have to watch out for ordered vs. unordered sets as well as with/without replacement. Overall one of the most irritating "easy" math topics. _________________
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bclare

Joined: 21 Jun 2008 Posts: 6048 Location: Boston
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Posted: Fri Nov 04, 2011 6:47 am Post subject: |
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slfan68 wrote: | So I'm in Math 122 here at my University, which is basically Calculus I and is also a M Tu W Th F course. However, I have quite possibly the worst teacher ever to teach at all. I took Calculus in high school last year, so I have a pretty good idea of how things work. However, she does not explain things like theorems at all. She writes them on the board and then proceeds to just working out problems. AND THEN, when she's working out problems on the board, she will, multiple times per class, make very stupid mistakes yet she continues to work the problems. Sometimes we catch her mistakes as soon as she makes them, but often if she makes a mistake on something she is just teaching us, there's no way we can know that she's making a mistake. AND THEN (it gets more cool), on tests we are given some of the most ridiculous problems she can think of. Problems that, instead of testing that we know the Calculus concepts, instead end up testing how well we can do extensive amounts of Algebra. And we aren't allowed to use calculators of any kind. The combination of ridiculous problems with an incapable teacher make this the biggest joke of a class I've ever seen. However, I need to somehow pull my grade up to at least a B, or I'm going to risk losing my scholarship. So frustrating
EDIT: I forgot to mention the teacher is on academic probation from the University for having consistently terrible pass/fail rates in her classes. Just one more thing to make me love college -.- |
The thing is, for anyone with a PhD in math, algebra (read: anything below calculus) is completely trivial, and should be done easily. Not that it's the same for you, but that might be how the prof feels about it.
Honestly unless you're going to be an engineer algebra is more useful for you than calculus will be. Until then, feel free to ask in here if there's anything you have trouble with, other than your teacher  _________________
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Brockbfball1563 


Joined: 29 Apr 2007 Posts: 3245 Location: Rochester, NH
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Posted: Sat Nov 05, 2011 4:31 am Post subject: |
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I can't be the only one who like's Calc but absolutely DESPISES linear algebra. Seriously, anything where I have to deal with vectors just makes me want to quit everything.  _________________
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Sixen


Joined: 11 Oct 2006 Posts: 1201 Location: Johnstown, NY
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Posted: Sat Nov 05, 2011 5:29 pm Post subject: |
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Brockbfball1563 wrote: | I can't be the only one who like's Calc but absolutely DESPISES linear algebra. Seriously, anything where I have to deal with vectors just makes me want to quit everything.  |
You're not. |
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conlan22 


Joined: 25 Aug 2007 Posts: 1542
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Posted: Sat Nov 05, 2011 11:05 pm Post subject: |
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Brockbfball1563 wrote: | I can't be the only one who like's Calc but absolutely DESPISES linear algebra. Seriously, anything where I have to deal with vectors just makes me want to quit everything.  |
yeah it's retarded. It seems like the stuff is either so easy you have trouble paying attention or so complicated it's hard to pay attention lol. |
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bclare

Joined: 21 Jun 2008 Posts: 6048 Location: Boston
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Posted: Sun Nov 06, 2011 2:23 am Post subject: |
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I didn't pay much attention in linear algebra when I took it, but I like it a lot more now. Calculus is kinda boring honestly, it's too methodical, you can get all the right answers without really understanding what you're doing. Linear algebra you actually have to understand what's going on; of course that means it's even more of a pain if you have a crappy teacher. _________________
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-Sparks-

Joined: 07 Oct 2007 Posts: 53
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Posted: Thu Nov 17, 2011 7:12 am Post subject: |
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I REALLY like math. Always liked it my whole life, I'll never forget my 770 score on the Math SAT's (missed one question... FFFFFFFFFFFFFUUUUUUUUUUUUUUUUUUUUUU...)
But how do I deal with a teacher who cancels class half the time? We have four units to cover in our calc III class. We started on Aug. 31, have only six class sessions left (twice per week) and we haven't even taken the second test yet... >_< I've taught myself to teach out of the book, like I can just "get" the concepts without any additional assistance besides the textbook. (Taught myself gradients and iterated integrals today, I find it fascinating that math seems to be a never-ending learning process, and I never wanna stop learning.) So I don't need a teacher to learn, but I still gotta take the tests just like everyone else. He always starts teaching 20 minutes late too. It'a a shame that my learning of math is slowed by this.
I had this same teacher for Calc II, and we missed so much class time that we had to drop parametric equations, the disk/shell methods, and quite a few other things. And parametric equations are essential in Calc III... I'm just hoping something really stupid doesn't happen like I'll have to repeat Calc III only because of my teacher canceling half the classes, which I have no control over (I already have to take a credit overload next semester...) And if he just bags some of the later material, I (and the rest of my class) will probably encounter that material later in our studies and have no fucking clue what it means.
As far as actual math goes, as much as I like math... fuck finding the normal vector to a vector-valued function at given points. There's so much to calculate and it's some of the hardest algebra I've ever seen... the tangent vector, the derivative of the tangent vector, the magnitude of the derivative of the tangent vector... with trigonometry it's not so bad cause of trig identities, but for algebraic functions... just no.
(Also I'm taking Linear Algebra next semester, I know it involves matrices but other than that I don't know what to expect...) _________________
"Listen, Harvard. I'm a billionaire. And most of you are gonna graduate, and move back in with your parents! I'm gonna tell you somethin', though. We [all] have something in common: we're all gonna die. No matter whatcha' do, no matter whatcha' do with your lives, you're dead! You're dead! You're dying. You're gonna die, all of you, dead. You, dead. You, dead, all of you."
-Nathan Explosion |
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