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Mathematics

From algebra to calculus, from trigonometry to set theory, it's all here.

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  1. From basic sequences, series and calculus, to measure theory, complex analysis and more advanced topics.

    • 1.2k posts
  2. Set theory, groups and ring theory, linear algebra, and other algebra-related topics.

    • 538 posts
  3. Home to threads on more applied (but non-physical/mechanical) threads; e.g. applied group theory or statisics.

    • 479 posts
  1. Started by violetendncy,

    Hello friends, it has occured to me that I know depressingly little about mathematics in general. I mean, I can do all the stuff in class they want you to do, but I really am not comfortable with any of the stuff. In saying this, I mean that I feel as though there are certain things I haven't learned....probably because they were attempted to be taught to me by southern women entertaining too many children.... Anywise, I was fiddling around with a circle the other day, and I wrote a TI-BASIC program that computes the Pi constant from scratch. If any of you are interested, here is the code (Ti-83 plus): :PROGRAM:CIRCLE :ClrHome :Input "Radius:",R :0-->F :…

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    • 12 replies
    • 2.8k views
  2. Started by youngone,

    Recently, I was looking through my sister's Maths Textbooks and I saw a very interesting topic I could learn. So for the next few days I learnt the basics of permutations and their applications. All was well until I stumbled upon a question that I was unable to solve. With no one else to turn to (my sister has not yet been taught permutations yet), I decided to post my question on the boards. The question goes like this: There are 9 books arranged on a shelf. 2 of them are labelled A, 3 of them are labelled B and 4 of them are labelled C. How many permutations of the books are there if: a)none of the books labelled A were next to each other. b)none of the …

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    • 2 replies
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  3. Started by kingjewel1,

    how do i work out that if a machine is worth $15000 and if it's price decreases by 20% per annum that it will cost $9600 in two years using Sn=a(r^n-1)/r-1? using this formula it doesn't work.... thanks guys

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    • 2 replies
    • 1.2k views
  4. Started by kingjewel1,

    hi there. would you mind helping me a lil with this one. it's sinx=1/2+cosx i think its really easy to solve but i can never get a positive value for it. i tried substituting Cos2x=1-2sin^2x also tried it it with sec^2x=1+tan^2x i know there's 1 positive and 1 negative value at least. between 0 and 2pi thanks in advance

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    • 2 replies
    • 1.3k views
  5. Started by dvjustus,

    Trying to come up with a function that fits (0,0) (1,1) (2,3) (3,7) (4,15) (5,31) (6,63)... If not too much trouble, help please. Thanks.

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    • 14 replies
    • 2k views
  6. Started by lama,

    Cantor's second diagonal method is not form N to P(N) because each element in the list is only a non-accurate representation of R member, for example: Epsilon = Invariant Proportion About 3.14... = circumference/diameter: Let us say that Epsilon is equivalent to the invariant proportion that can be found in the triangles below. (VERY IMPORTANT: When Epsilon = Invariant Proportion, then there is no connection to words like 'smaller' or 'bigger' or 'size' or 'magnitude' or 'Quantity', and the reason is clearly explained) , |\ | \ | \ | \ | | | |\ | | \ | | \ | | \ | | | | | |\ | | | \ | | | \ | |…

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    • 1 reply
    • 1.5k views
  7. Started by lama,

    One of the most devastating things in the Language of Mathematics and its logical reasoning is a hidden assumption, and the worst thing is a first-order hidden assumption. Let FOHA be a First-Order Hidden Assumption. Let UQ be Universal-Quantification. Is there a FOHA in the way we use UQ concept? The UQ is based on the term ‘For All’. The meaning of the word ‘All’ is synonym to the word ‘Complete’ and if it is related to a collection of elements, then from a quantitative point of view ‘All’ is actually the SUM of this collection, where in the level of SUM we are no longer in the level of each single element that exists in this collection. The SUM …

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    • 68 replies
    • 10k views
  8. Started by alt_f13,

    Binary, sure. Base four? Okay, its a little more managable than binary, and base 16 is in full use throughout computing... but base 10? Why not make it base 7.5? That's just as useless. What's with the base 10 numbering system? What a stupid system. I seriously cannot understand how we still use such a primitive numbering system in this day and age. Well, I can... but it is time for revolution! Aside from my rant, what would be the best numbering system for the future? 1,4 or 16? Or something completely different? I don't know about you guys, but I stopped counting on my fingers when I graduated teh preeskule.

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    • 13 replies
    • 2.6k views
  9. Started by Kedas,

    Hi, Does someone know where the mass centre of a half sinus period is located? I know pi/2 on the x-axes but on the y-axes ? to give an idea for a half circle it's located at R*4/(3*pi) that is 0.42 for R=1

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    • 14 replies
    • 9.2k views
  10. Started by lama,

    Epsilon = Invariant Proportion About 3.14... = circumference/diameter: Let us say that Epsilon is equivalent to the invariant proportion that can be found in the triangles below. (VERY IMPORTANT: When Epsilon = Invariant Proportion, then there is no connection to words like 'smaller' or 'bigger' or 'size' or 'magnitude' or 'Quantity', and the reason is clearly explained) , |\ | \ | \ | \ | | | |\ | | \ | | \ | | \ | | | | | |\ | | | \ | | | \ | | | | | | | |\ | | | | \ | | | | | | | | | |\ |____|____|___|__|_\ Each arbitrary right triangle's area is smalle…

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    • 98 replies
    • 13k views
  11. Started by BrainMan,

    Given a>0 solve the equation: xx[a(a+1)]) = a.

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    • 11 replies
    • 2.6k views
  12. Started by noz92,

    I know that imaginary numbers are numbers that are based on [math]i[/math] [math]\sqrt{-1}[/math], but why are they imaginary. Why can't there be [math]\sqrt{-n}[/math]? Why can't you have a product a negative number, yet you can have a sum?

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    • 21 replies
    • 3.8k views
  13. Started by Daymare17,

    A mathematical proof is counted as valid if it is consistently verifiable using accepted axioms. But how about these axioms? Let us take the most fundamental and universally accepted axiom (in fact, it's so universally accepted that it hasn't even been officially listed as one). Let's take the axiom 1 = 1, or x = x. In first grade books, integers are depicted as fruit. An apple plus an apple equals two apples. This is a useful concretisation. If mathematics is correct, then this kind of concretised example must be correct, since "the proof of the pudding is in the eating" - the proof of the theory is in its applicability to the real world. There are serious probl…

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    • 76 replies
    • 14.6k views
  14. Started by Primarygun,

    How does radian bring convenience to us? Could anyone tell me?

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    • 19 replies
    • 3.5k views
  15. Guest nadine12
    Started by Guest nadine12,

    Could anyone be so kind enough to help me with this question and show me the working so I can understand how you got the answer??? I shall have to write the square root as an actual word: square root b squared - c squared, find the positive value of b given a=5.6 and c=4.4. Thankyou ever so much. Nadine

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    • 7 replies
    • 2.6k views
  16. Started by mab,

    Hi, Who designed the shape of "0" for zero. mab.

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    • 28 replies
    • 4.7k views
  17. Started by bloodhound,

    This week we are rewarding the What People Think is The Most Used Theorem In the Whole Of Physics, Chemistry, Biology and obviously Mathematics. Place your nominations NOW!!!. voting will commence on 1st of January!! Current Nominees:- 1)Pythagoras's Theorem 2)Fundamental Theorem of Calculus 3)Chain Rule Note: natural selection removed due to the fact that its not a theorem and general displeasure among the formites. If you want it back, you will have to put up a strong case for it

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    • 17 replies
    • 2.4k views
  18. Started by grayfalcon89,

    Prove that any five consecutive integer is divisible by 5 such that the least term is > 0. Prove that any two integer's sum is NOT always divisible by 3. State why this is and tell in what case is this possible. Prove that: [math]\binom {n}{k}[/math] equals [math]\binom {n}{n-k}[/math]

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    • 7 replies
    • 2.5k views
  19. Guest FSC729
    Started by Guest FSC729,

    Hello everyone I have a website dedicated to helping people learn any type of math and physics. At first it started out as a website helping people how to do proofs, but then I expanded out to physics as well: http://fsc729.ifreepages.com/ In my forum I have links to partial solution sets for popular textbooks, book reviews and more. In addition I have a link to totally free online textbooks. Please visit my website and if you have any ideas you want to share you can sign my guestbook or post in my forum. It is completely free, Thank You John G.

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    • 1 reply
    • 1.4k views
  20. Started by Proton Head,

    I'm trying to think over one theory, but I need to solve this equation group and I've come to a full stop. (a*b^2)/c = h b^3/(a*c^2) = G (a*b^3)/(c^2*d^2) = k (a*b)/d^3 = M So trying to solve a, b ,c and d. Any help would be appreciated. Thanks!

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    • 15 replies
    • 2.9k views
  21. Started by cheem,

    Hi, For a number like 45 915, are both ways of writing that number below in words correct? Is there a more standard way? Forty-five thousand, nine hundred and fifteen. Forty-five thousand and nine hundred and fifteen. Thanks in advance and sorry for asking such a basic question here

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    • 7 replies
    • 1.8k views
  22. Started by ydoaPs,

    is there a way to graph imaginary values on a cartesian coordinate system? for that matter, is there any other way to graph them?

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    • 7 replies
    • 2.2k views
  23. Started by Scott,

    ... I dont know where to start. School is too slow for me, and geometry isnt really advanced (im in 9th grade). Its basically all remembering posulates and then applying them to proofs. So I want to get ahead of the game and get into Algrebra 2 (for some reason Florida likes to go from Algebra one to Geometry and then go on to Algebra 2). Does anyone know any good websites or eBooks to help me get started?

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    • 19 replies
    • 3.1k views
  24. Guest Granta
    Started by Guest Granta,

    Hi there, I've a question here that I'd like yer opinions on: If I have an n*m matrix X made up of n measurements of m variables (assuming all the variables measure temperature and so the units are Kelvin (K)). Does this imply that the covariance of X has units K^2? Also, if S = covariance(X) and S = ULU', what are the units of U, L and U'??

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    • 0 replies
    • 1.1k views
  25. Guest fornorton
    Started by Guest fornorton,

    Hi there! I am trying to calculate the complexity of an algorithm and I have concluded that it takes a number of steps given by the following formula (in Mathematica notation): Hypergeometric1F1(-D, 2, -x) This looks like a multinomial of x. The order of this polynomial is D. The last term of this polynomial is x^D/D!, which converges to 0 when D is large enough. On the contrary, the first terms seem to be significant. Do you have any suggestions for the complexity of the algorithm? Is it polynomial or exponential with respect to D? Thanks in advance!

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    • 5 replies
    • 2.4k views

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