set

  1. R

    Sets functions and iterations

    I am new to algebra and help would be more than welcome to tell me if the process I have built is OK, and if my attempt to apply formula on two sets to create a new one is also OK. Context I have a database containing species records (e.g. 10 different species, with 100 rows by species ; in...
  2. J

    Geometry Construction Set

    Hello, You may be interested in my Geometry Construction Set: https://github.com/jfbouzereau/geom Best regards JFB
  3. Chemist116

    How can I find the mass of a sphere held in a set of wires hanging from two roofs?

    The problem is as follows: The figure 1. shows a diagram where a sphere is hanging from two roofs and it is an equilibrium. Find the mass of the sphere. You may consider that gravity is $10\frac{m}{s^2}$. $\begin{array}{ll} 1.&50\,kg\\ 2.&20\,kg\\ 3.&30\,kg\\ 4.&60\,kg\\ 5.&25\,kg\\...
  4. M

    what's the formula for this set ?

    I need to know the formula which gives these variables ! 2, 12, 24, 37.8947368, 53.333, 70.0811111, 87.9709414
  5. Split39

    I have a few questions about set theory ,Please help

    I am not sure whether this is the right section to ask this question. I want to learn Set theory from the basics for an exam I want to attend next year. I don't know where to begin. Can someone recommend some websites or books? Thanks.
  6. E

    On the set N × N, define the following relation: (a, b) ∼ (c, d) if and only if a + d

    On the set N × N, define the following relation: (a, b) ∼ (c, d) if and only if a + d = b + c. (1) Show that this is an equivalence relation (2) Describe the equivalence class of (1, 1)
  7. J

    Unique combinations of set

    Let’s say i have set with the elements { 1,2,3,4,5,6,7,8,9,10,11,12,13,14}. Is there a formula how I can calculate how many unique combinations (the order of the elements are not relevant) there are possible. And this combination can be of every length (can have a length of 1, but also...
  8. N

    Is B not a set in Russell Paradox ?

    Does Halmos conclude B is not a set (Page 7 and 11 in Naive Set Theory)? Book Link from google: https://piazza.com/class_profile/get_resource/is25bi6c6o1oh/isv14pknyni2z3
  9. L

    Null set paradox

    Paradox: if any member, or lack thereof, in the null (i.e., empty) set is countable, it requires the concept of zero, so it is not truly empty.
  10. B

    Find THE MEAN OF THE SET?

    2,5,7,3,3} What is the mean of this sequence , help me please because it is my first time doing it today and I'm a bit confused . Thanks
  11. Chikis

    Find the cost of a set of pens

    The cost of a set of books is twice the cost of a set of pens. The cost of a set of pens is three times the cost of a set of pencils. Find the cost of a set of pens if N 4 000 is used in buying the three sets of the items. cost of a set of books = 2(cost of set pens) cost of a set pens = 3(cost...
  12. P

    Set operations.

    https://en.m.wikipedia.org/wiki/Set_(mathematics) Various Set operations like Union, Intersection, Complement, Cartesian product etc are shown with Circle as Geometrical figure. Other than Circle Geometrical shape, Which could be other Geometrical shapes where these operations can be...
  13. G

    An infinite set of finite sequences of combinations of a finite set of elements

    An infinite set of finite sequences of combinations of a finite set of elements is an infinite uncountable set?
  14. J

    Why is the set of rational numbers dense, and set of integers numbers not?

    If we have two sets: Set one is the set of rational numbers with the usual less-than ordering Set two is the set of integers numbers with the usual less-than ordering Why is the set of rational numbers dense, and set of integers numbers not? Density is that for all choices of x and y with...
  15. B

    Axiomatic set theory ZFC is inconsistent thus mathematics ends in contradiction

    Axiomatic set theory ZFC is inconsistent, thus mathematics ends in contradiction: http://gamahucherpress.yellowgum.com/wp-content/uploads/MATHEMATICS.pdf Axiomatic set theory ZFC was in part developed to rid mathematics of its paradoxes, such as Russell's paradox. The axiom in ZFC developed...
  16. M

    set problem

    given that n(PnQ)=n(PnQ)' find x and hence the U
  17. N

    Check, for constructing nice set of linear equations

    Hi Well, I was struggling with solving these linear equations for days. more accurately, It solved but the answers do not check with what I have, so want to find where I have mistaken. It would be appreciated if you can check with me that my understanding is correct for the problem. (do not...
  18. J

    Set Theory Question

    Hard set theory question please help ASAP Out of a group of boys, 36 don’t have PS4, 70 don’t have an XBOX, whilst 61 have both a PS4 and an XBOX. If 68 boys have one or other machine, but not both, then how many teachers are in the group?
  19. K

    Number of elements in set

    A N B is not empty set A U B has 17 elements Number of subsets of A N B = n (A - B) Theb what is the minimum number of elements of B? Answer is 9 but i can not get there I drew Venn diagram and said a+b+c = 17 (these are my cariables), 2^b = a and then 2^b + b +c = 17 But then...
  20. K

    Number of elements in intersection set

    A and B are two sets. A N B is not empty set and n ((A-B)) U (B-A)) = 26 and n (A) =20 . What is the minimum number of elements B must have ? N denotes intersection, n denotes number of elements Answer is 8 but why? I said A has 19, intersection has 1, and B-A = 6 , So this makes B...