22 Mar 2011, 10:46 am
22 Mar 2011, 12:03 pm
22 Mar 2011, 12:39 pm
23 Mar 2011, 1:06 am
JoeSchmukapop wrote:
MasterJedi wrote:
I'm 38 and am lucky if I can understand the addition of fractions.
I'm the exact same. Wait until you have to subtract them.
Subtraction is virtually the same as addition. As long as one subtracts a smaller number from a larger, all is well. Addition has no such constraints.
Well that is not exactly true. One can reformulate the "carry" and "borrow" rules so that subtraction and addition work exactly the same way which is the underlying truth.
Given a and b there exists x such that a + x = b. That is true regardless of magnitudes.
ruveyn
23 Mar 2011, 10:07 am
What annoys the most is that I can see enough of mathematics to know that it is a very beautiful thing, and something which I would otherwise have enjoyed immensely - except for the inconvenience that it all just slides off me.
Nothing sticks, and I struggle to manage 'not quite getting it'. 
23 Mar 2011, 10:42 am
ruveyn wrote:
JoeSchmukapop wrote:
MasterJedi wrote:
I'm 38 and am lucky if I can understand the addition of fractions.
I'm the exact same. Wait until you have to subtract them.
Subtraction is virtually the same as addition. As long as one subtracts a smaller number from a larger, all is well. Addition has no such constraints.
Well that is not exactly true. One can reformulate the "carry" and "borrow" rules so that subtraction and addition work exactly the same way which is the underlying truth.
Given a and b there exists x such that a + x = b. That is true regardless of magnitudes.
ruveyn
I can easily work with fractions, but I usually convert to decimal, or an expression of the form A/B to A * B^-1. It means fewer rules to memorise
In your case, assuming there isn't any X's or Y's in there, just convert to decimal
23 Mar 2011, 11:33 am
ryan93 wrote:
I can easily work with fractions, but I usually convert to decimal, or an expression of the form A/B to A * B^-1. It means fewer rules to memorise
In your case, assuming there isn't any X's or Y's in there, just convert to decimal
In your case, assuming there isn't any X's or Y's in there, just convert to decimal
Converting to decimal is usually a very ugly way of doing it. Consider fractions of the form a/(np), where a is some integer, n is any integer, and p is any prime other than 2 or 5. They are extremely clumsy to deal with in decimal notation, and they occur with sufficient frequency that I would not want to deal with the hassle. Converting to decimal only properly works with fractions where the denominator's prime decomposition consists only of 2s and 5s.
23 Mar 2011, 12:09 pm
23 Mar 2011, 3:58 pm
ryan93 wrote:
Orwell wrote:
ryan93 wrote:
I suck at maths. I'm okay at playing with linear algebra, and probabilities, but I'm awful enough when it comes to something highly abstract like calculus (and it is abstract, despite it's uses 
). Though the fact my mathematical education has continued into college implies I suck at a higher level than the majority of the populace 
). Though the fact my mathematical education has continued into college implies I suck at a higher level than the majority of the populace I don't understand how calculus is abstract- it seems like the most intuitive and physically concrete form of mathematics I can think of. Linear algebra would have to be at least as abstract, usually more so.
The ideas behind it, like differentiation, integration, the squeeze theorem, are intuitive, but at soon as you start applying them to complex enough functions (x^(4x^2 + 5)) you loose a lot of the intuition. That, and the fact that halfway through semester two we still havn't seen a single proof for any of this stuff
They should've been covered in infinite limits. Anyway, here they are.
Quote:
Linear Algebra is at least a lot more tangible; Markov Chains and simultaneous equations relate to real world phenomena through pretty basic math, while Functions can be derived/integrated easily enough, but it rarely makes much sense how one function led to another. But that's probably just me
Linear Algebra/Matrix Theory is pretty abstract. I remember linear transformation being capable of some weird stuff.
Last edited by Biokinetica on 23 Mar 2011, 4:22 pm, edited 1 time in total.
23 Mar 2011, 4:18 pm
23 Mar 2011, 7:08 pm
23 Mar 2011, 7:16 pm
23 Mar 2011, 7:18 pm
Orwell wrote:
ryan93 wrote:
It depends what you are computing, or how accurately you want to compute it. There are cases where you really don't want to expand the fraction to decimals. If I'm trying to work out something to give myself an idea about a real world concept (how much copper in 20,000 747's, probability of event x) I often to approximate the fractions as a fraction with prime decomposition 2 or 5. For pure maths, it's not a great idea. Accuracy is paramount; an answer that is nearly right isn't right, as they say.
I just prefer not to introduce unnecessary rounding errors. There are software packages that are capable of storing fractions in exact form.
Quote:
Excel is generally a godsend though for messing around with Data from lab, or any tedious calculations.
Do not use Excel! It is a deeply, deeply flawed program that is completely unsuitable for all but the most trivial tasks (and even then it isn't terribly trustworthy). If you must use spreadsheets, use either LibreOffice Calc or Gnumeric; the authors of those packages would actually be capable of passing a high school math course.
The rounding errors would usually only be found on my "back of the envelope" or "in my head" calculations; i.e. one's I can afford to have a 10% error margin in.
As for Excel, I only use it for the most trivial tasks these days after you warned me it sucks, but even at that I've noticed it actually introduced slight rounding errors, and some stupid problems when messing with the address function. I'm giving up on "spreadsheet programming" soon anyway, I'm going to try and learn R/Mathematica, preferrably the latter because it is less about coding and more about bog standard functions and arithmetic tricks
23 Mar 2011, 7:28 pm
ryan93 wrote:
I'm going to try and learn R/Mathematica, preferrably the latter because it is less about coding and more about bog standard functions and arithmetic tricks
Mathematica's fun, but it's a pain to try and get a legit copy of it. It's a few thousands bucks if you want to purchase your very own copy that you're actually allowed to use for stuff. You can get a student edition for a couple hundred if you agree not to do anything with it. Since finishing my Mathematica course at school, I've been toying around a bit with WxMaxima. It does basically the same stuff as Mathematica, with slightly different syntax and a bit less polish, but it's free.
R has a completely different purpose than programs like Maxima/Mathematica/Maple. It's useful to know R if you're going into any scientific field, but based on your age it's probably not urgent... I still don't know enough R to do anything useful with it.
23 Mar 2011, 8:12 pm
Orwell wrote:
ryan93 wrote:
I'm going to try and learn R/Mathematica, preferrably the latter because it is less about coding and more about bog standard functions and arithmetic tricks
Mathematica's fun, but it's a pain to try and get a legit copy of it. It's a few thousands bucks if you want to purchase your very own copy that you're actually allowed to use for stuff. You can get a student edition for a couple hundred if you agree not to do anything with it. Since finishing my Mathematica course at school, I've been toying around a bit with WxMaxima. It does basically the same stuff as Mathematica, with slightly different syntax and a bit less polish, but it's free.
R has a completely different purpose than programs like Maxima/Mathematica/Maple. It's useful to know R if you're going into any scientific field, but based on your age it's probably not urgent... I still don't know enough R to do anything useful with it.
Yeah, I've been considering buying a hobby licence when I get work during the summer. One of the main pro's about mathematica is that is has a pretty intuitive synthax, but I'll have a look at WxMaxima.
I think there are half-courses in Scientific Computation in my degree, did you find yours to be worth taking? My friend says it's pretty unlikely that someone could get a good understanding of programming by being self taught...
23 Mar 2011, 9:59 pm
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