What is Cartesian: Definition and 558 Discussions

In mathematics, specifically set theory, the Cartesian product of two sets A and B, denoted A × B, is the set of all ordered pairs (a, b) where a is in A and b is in B. In terms of set-builder notation, that is




A
×
B
=
{
(
a
,
b
)

a

A



and



b

B
}
.


{\displaystyle A\times B=\{(a,b)\mid a\in A\ {\mbox{ and }}\ b\in B\}.}
A table can be created by taking the Cartesian product of a set of rows and a set of columns. If the Cartesian product rows × columns is taken, the cells of the table contain ordered pairs of the form (row value, column value).One can similarly define the Cartesian product of n sets, also known as an n-fold Cartesian product, which can be represented by an n-dimensional array, where each element is an n-tuple. An ordered pair is a 2-tuple or couple. More generally still, one can define the Cartesian product of an indexed family of sets.
The Cartesian product is named after René Descartes, whose formulation of analytic geometry gave rise to the concept, which is further generalized in terms of direct product.

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  1. N

    Proving the cartesian product.

    hello all, i'm trying to prove the cartesian product cardinality property of the cartesian product. on a first attempt i used this: and on a second attempt this: this is the first of many small exercises I'm doing for building a strong theoretical computer science background. i...
  2. K

    Cos^2(φ_1) +cos^2 (φ_2) + cos^2(φ_3) = 1 in a three dimensional cartesian system

    Homework Statement I seem to be stuck for an assignment that I have for one of my classes, in which we are asked to prove that cos^2(φ_1) +cos^2 (φ_2) + cos^2(φ_3) = 1 in a three dimensional cartesian system, where φ_1 ,φ_2, φ_3 are the angles that a random vector r (x,y,z) is to the x,y and z...
  3. H

    Parametric Representation in Spherical and Cartesian coordinates

    Give a parametric representation of the following surfaces in terms of the given parameter variables: a) The first octant portion of the sphere (x^2) + (y^2) + (z^2) = 16 in terms of the spherical variables theta and phi. b)The graph of the function z = (x^3) - sqrt(y) in terms of the...
  4. S

    Converting complex numbers into cartesian and exponential form

    Hey, I'm not too sure if this is pre-calc or not because it's in a different course but I think I remember doing this in pre-calc a long time ago... 1. Determine cartesian(z = x + jy) and exponential(\rhoe^{j\theta}) forms of the following complex numbers: z = 3 + 5j 2. I have no...
  5. G

    Set size of a cartesian product

    Set S with n elements! Set size of {<x,y> | (X,Y are proper subsets of S), (X union Y = S)! I tried doing something, but I'm stuck staring at a closed door, so I need a fresh start! Any hints would be appreciated!
  6. S

    Parametric Equation to Cartesian

    Homework Statement Find a Cartesian equation relating x and y corresponding to the parametric equations x = \frac{2t}{t^3+1} y = \frac{9t^2}{t^3+1} t \neq -1 Write your answer in the form P(x,y)=0, where P is a polynomial in x and y such that the coefficient of x^3 is 729. 2...
  7. M

    Vector Spaces: Cartesian vs Tensor products

    Hi, I have a problem understanding the difference between Cartesian product of vector spaces and tensor product. Let V1 and V2 be vector spaces. V1 x V2 is Cartesian product and V1 xc V2 is tensor product (xc for x circled). How many dimensions are in V1 x V2 vs V1 xc V2? Thanks, Monte
  8. Y

    Expressing a Field in Spherical Coordinates as Cartesian Vectors

    Homework Statement A field is given in spherical coordinates as F=[cos(θ)/r2]∙ar+[sin(θ)/r]∙aθ. Express F in terms of x, y, z, ax, ay, azHomework Equations ar∙ax=sin(θ)cos(∅) ar∙ay=sin(θ)sin(∅) ar∙az=cos(θ) aθ∙ax=cos(θ)cos(∅) aθ∙ay=cos(θ)sin(∅) aθ∙az=-sin(θ) x=r*sin(θ)*cos(∅)...
  9. J

    Finding the components of a Cartesian vector

    Homework Statement Picture is attached Homework Equations The Attempt at a Solution I feel like I am right and the computer is wrong, but I just wanted to check here first. I attached a picture of the problem and my answer. This is how I solved the problem: Fz=750sin(45)=530.33N...
  10. J

    How to Express the force as a Cartesian vector?

    I am having trouble solving this problem, I also have it attached: http://i160.photobucket.com/albums/t193/John123321_bucket/Capture.png Here is a short version of how I got my answers, but it says it’s wrong: X=500cos(30)=433N i= 433sin(45)=306.2 j=-433cos(45)=-306.0...
  11. G

    De Moivre's theorem in Cartesian form.

    Hey Guys, I've been passed this from a friend to help them out, but I don't know much about it. So this is a bit of annoying first post... SORRY! Homework Statement if z = √2 + i, use de Moivre's theorem to find z^5 in Cartesian form. AND. Convert z = -8 + 8 √3 i to polar...
  12. H

    Can we observe the motion of a photon in cartesian space?

    Hi all! Is it possible to derive x-y-z vectors of c in 3d cartesian space? Is there any way we could then observe the photon (or measure its speed) in parallel with x-axis for example? Thanks.
  13. A

    Cartesian product of separable metric spaces

    Dear readers, Let X be the product space of a countable family \{X_n:n\in\mathbb{N}\} of separable metric spaces. If X is endowed with the product topology, we know that it is again separable. Are there other topologies for X such that is separable? Is there a natural metric on X such that X...
  14. T

    Indexed Cartesian Product as sets of functions

    I'm going through the set theory material in the appendix of Knapp's Basic Algebra. I want to make sure that I understand what he says is the set theoretic notion of the indexed cartesian product, \prod_{x\in S}A_{x}. He says that this can be thought of as the set of all functions...
  15. X

    Polar to cartesian coordinates for stream function

    Homework Statement Consider a velocity field where the radial and tangenetial components of velocity are V_r=0 and V_theta=cr, respectively, where c is a constant. Obtain the equations of the streamlines. Homework Equations x=rcos(theta) y=rsin(theta) The Attempt at a Solution I...
  16. 1

    HELP cartesian form vector help

    URGENT HELP! cartesian form vector help! Homework Statement given the following vectors, calculate Adotb and BxA. Express your answers in cartesian Form A= +6X-3Y+4Z B= -3X+1Y-5Z Homework Equations The Attempt at a Solution My teacher went over this in about five minutes making...
  17. K

    Calculating Arc Length on a Circle with Cartesian Coordinates

    Homework Statement The Carteian coordinates of a point on a circle with its center at the origin are [0.40, 0.30]. What is the arc length measured counterclockwise on the circle from the positive x-axis to this point? Homework Equations The Attempt at a Solution Wouldn't they be...
  18. S

    Calculating string given index in Cartesian Set

    Hello all, I'm new, so please go easy on me if this is a silly question. If I have a source set of characters, say: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~ " And I compute the Cartesian product of this source set (sort of). This gives...
  19. W

    Cartesian products and the definition of a map

    Hello, I was wondering if there were alternative definitions to a "function" ( alternative to the standard f is a subset of A X B if f : A -> B ). I was introduced to the "general" definition of a cartesian product ( with respect to an indexing set H ) , it is weird to me because the general...
  20. G

    What Heading and ETA Will Get Me to City B?

    Homework Statement A pilot wishes to fly form city A to city B, a distance of 720 km on a bearing of 070°. The speed of the plane is 700 km/h. An 60 km/h wind is blowing on a bearing of 110°. What heading should the pilot take to reach his or her destination? How long will the trip take? Use...
  21. S

    Path Integral - Cartesian to Polar Coordinates

    Homework Statement Transform to polar coordinates and evaluate... \int^{a/\sqrt{2}}_{0} dx\int^{\sqrt{a^2-x^2}}_{x}\sqrt{x^2 + y^2}dy Homework Equations x^2 + y^2 = r^2 x = r cos \theta y = r sin \theta I've been struggling to make sense of this problem, it should be easy, I'm...
  22. E

    Distance from cartesian coordinates and im going wring somewhere.

    Why is \sqrt{9+36} = 3\sqrt{5} and not 6.708 ? I wasnt interested in maths at school but now I'm trying to self teach, so pardon my ignorance. Edit: Ok i feel foolish now, no need to correct me as I've just worked out i WAS correct. I'm still unsure as to why it would be shown...
  23. C

    Cartesian product help?I'm interested how to solve the following problem:

    I'm interested how to solve the following problem: if we have a triangle, where a,b,c are sides of that triangle and we know that (a+b+c)x(a+b-c)=3ab, we need to find the angle opposite to side c. How to do this?
  24. U

    Change to cartesian double integral to polar coordinates and evaluate

    Homework Statement integrate 1/((1+x^2+y^2)^2) dx dy Both x and y going from 0 to infinity Homework Equations x^2+y^2 =r The Attempt at a Solution After that I get 1/(1+r^2) ^2 Cannot visualize the function, do not know what the limits are. If I could have any help it...
  25. O

    Cartesian torque to Spherical Coordinates

    I'm writing a function for Matlab and I'm trying to figure out how to apply a torque matrix in cartesian coordinates to an object in spherical coordinates. The short story is this: For interest's sake, a friend and I have written a function with creates a tree which random branch...
  26. R

    Determining a Cartesian equation given a point and a line

    Homework Statement Given the point P(-2,0,6) and the line "x-4/3= y+2/-5=z-1/2" determine the cartesian equation of the plane. Homework Equations the lines vector equation is (4,-2,1)+T(3,-5,2)The Attempt at a Solution using A(x,y,z) i attempted to find a directional vector for P...
  27. A

    Determine Cartesian eq given

    Homework Statement Determine the Cartesian equation for the plane with the following: 1) through the points (1,2,1) and (2,1,4) 2) parallel to x-axis Homework Equations Parametric Equations Vector Eqs Plane Eqs The Attempt at a Solution I basically understand how perpendicular...
  28. S

    Triple integral from cartesian to spherical coordinates

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  29. C

    Rewrite polar equation as Cartesian (trig identities)

    Homework Statement x=2acos(theta- pi/3)cos(theta) y=2acos(theta- pi/3)sin(theta) Write everything in terms of x and y Homework Equations cos(a-b)=cos(a)cos(b)+sin(a)sin(b) sina/cosa=tana etc... The Attempt at a Solution I've tried a lot of rearranging, can't figure it out.
  30. C

    Resolving a unit vector from Cylindrical coordinates into Cartesian coordinates

    Homework Statement Question 3 (a)A long metal cylinder of radius a has the z-axis as its axis of symmetry.The cylinder carries a steady current of uniform current density J = Jzez. Derive an expression for the magnetic field at distance r from the axis,where r<a. By resolving the...
  31. H

    Simple Cartesian Product Proof(s)

    Homework Statement Prove for all sets A, B, and C that: Ax(B^C) = (AxB)^(AxC) Homework Equations AxB is the Cartesian Product of A and B. That is, the set of all ordered pairs (x,y) such that x is an element of A and y is an element of B. ^ denotes intersection (and) The Attempt...
  32. P

    Finite cartesian product of connected space is connected

    "finite cartesian product of connected space is connected" hi am not able understand the theorem that.. "finite cartesian product of connected space is connected".. what is a base point? how it is related to homeomorphism? can anyone explian?
  33. B

    Cartesian Coordinates in Linear Algebra and Globality

    Hi, Everyone: I just read recently a comment to the effect that Descartes never intented his use of coordinates in his layout of analytic geometry to be used globally; there was also a follow-up comment about " no one really using any coordinates in a global way. Does anyone...
  34. 3

    Convert Longitude/Latitude to cartesian x,y

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  35. D

    Cartesian Vectors: Calculate Magnitude & Direction

    Homework Statement Andrew and David kick a football at the same time. Andrew kicks it with a force 155N and David kicks it with a force 210N. Angle between the two forces is 30 degrees. Calculate the magnitude and direction of the resultant force. Homework Equations Cosine law...
  36. C

    The units of a cartesian product?

    Find all units in Z12 X Z6 and their inverses. What i did was find the units of Z12 which are 1,11,5,7 then the ones of Z6 which are 1,5 and take the cartesian product of those two sets?
  37. Z

    Calculating Christoffell Symbols of Second Kind for Cartesian Space

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  38. J

    Off-axis magnetic field due to a current loop in cartesian coordinates

    Hi there, a few days ago I derived the probably well-know expression for the magnetic field of a current loop including elliptic integrals of the first and second kind (it can be seen here http://plasmalab.pbworks.com/f/bfield.pdf" ). As I'd like to rotate and shift the position of the...
  39. C

    Cylindrical and Cartesian Coord. dot product

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  40. G

    Problem: Cartesian tensor to Spherical Tensor

    Dear Frnds, my problem is very simple. please help me. I have a dielectric tensor like: epsilon_T= |1 0 0| |0 1 0| %% note that it is in cartesian co-ordinate system |0 0 a| now the potential...
  41. H

    Vectors in Cartesian Cylindrical Spherical

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  42. S

    Fluid Mechanics equations in Cartesian and Cylindrical coordinates?

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  43. L

    Electric field in cartesian coordinates

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  44. WannabeNewton

    Help on Jacobian Matrix for Cartesian to Spherical

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  45. W

    Taylor series for cartesian circle equation

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  46. Z

    Trouble converting integral from cartesian to spherical coords.

    Homework Statement Specifically, this question is about computing the expectation value of the Hamiltonian of a variational calculation of a hydrogen atom *neglecting the potential term. I'm assuming the trial wavefunction e^{-\alpha r}. The question, however, is purely math based, not...
  47. L

    Polar and cartesian coordinates

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  48. Q

    Bijective Mapping of Cartesian Products: X^{m} \times X^{n} to X^{m + n}?

    Homework Statement Find a bijective map g : X^{m} \times X^{n} \rightarrow X^{m + n} Homework Equations The Attempt at a Solution I don't even know where to begin. How would I map X^{m} \times X^{n} in the first place? How could I map X^{m + n}?
  49. Q

    Cartesian Products: Set of Ordered Pairs?

    Is the cartesian product (A \times B) the set of ALL POSSIBLE ordered pairs (a, b) such that a is an element of A and b is an element of b, or is it simply the set of "all ordered pairs?"
  50. T

    Find a Cartesian equation for the curve and identify it.

    Homework Statement Find a Cartesian equation for the curve and identify it. r = 3sin(θ)Homework Equations The Attempt at a Solution I know that the answer is as follows... r^2=3(r*sin(\theta)) x^2+y^2 = 3y x^2 + (y-\frac{3}{2})^2 = (\frac{3}{2})^2 I understand everything but the last part...
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