Geometry Definition and 999 Threads

  1. C

    Fractal Geometry and the Foundations of Maths

    Hey Everyone, I just wanted to ask for a bit of help on this research assignment I have to do. I have to show how Fractal Geometry contributes to the theory that Mathematics was invented. I have been looking into fractal dimensions and the fact that the dimensions we have labelled (1,2 and 3)...
  2. S

    Differential Geometry, curve length

    Homework Statement Homework Equations L[c]:=\int_{a}^{b}(\sum_{i,j=1}^{2}g_{ij}(c(t))c_{i}'(t)c_{j}'(t))^{1/2}dt The Attempt at a Solution So g_{ij}(x,y)=0 for i{\neq}j, c_{1}'(t)=-Rsin(t), c_{2}'(t)=Rcos(t) so...
  3. TrickyDicky

    What is the Geometrical Meaning of the Einstein Tensor?

    The stress-energy tensor is associated to a volume density and flux in 4-spacetime and the Einstein tensor seems to represent a three-dimensional curvature (being a one-form with vector values) that acts on and is acted by the stress-energy source. If this is correct, I'm not sure what is this...
  4. marcus

    Building SM Matter from Discrete Quantum Geometry

    String field from Loop SpinfoamQG:how to build SM matter on discrete quantum geometry note: EPRL is the current standard spinfoam formulation of Loop Quantum Gravity. http://arxiv.org/abs/1201.0525 String Field Theory from Quantum Gravity Louis Crane (Submitted on 2 Jan 2012) Recent work...
  5. M

    Prove: QR Passes Through O If PQ, PR on xy=c2 Inclined Equally

    Homework Statement Given that P,Q and R lie on the hyperbola xy=c2, prove that if PQ and PR inclined equally to the coordinate axes, then QR passes through O. Homework Equations The Attempt at a Solution I don't understand what does ''PQ and PR are inclined equally to the...
  6. M

    Can Geometry Help Solve This Vector Problem?

    Homework Statement (E) is a group of points M from a level/plane MA^{2}-MB^{2}=-4 And I is the center of [AB] Homework Equations show that IM*AB=-2 ( IM and AB have arrows on top) The Attempt at a Solution Well i split MA^{2}-MB^{2}=(MA-MB)(MA+MB) then i got ...
  7. M

    Find 4th Tangent for 2 Circles Coordinate Geometry

    Homework Statement 2 circles have the equation x2+y2-2x-2y+1=0 and x2+y2-12x-12y+36=0 respectively. Both circle touches the x-axis, y-axis and the line 3x + 4y = 12. Find the fourth tangent of the 2 circles. Homework Equations The Attempt at a Solution This is second part of the...
  8. M

    Coordinate Geometry: Finding the Locus of a Midpoint on a Curve

    Homework Statement A variable point P lies on the curve y2 = x3 and is joined to a fixed point A with coordinate (2,0). Prove that the locus of the mid-point of AP is y2= 2(x-1)3. Homework Equations The Attempt at a Solution According to what i know, I need to know the...
  9. J

    Could a Supermassive Black Hole be the Center of our Finite Universe?

    Astronomers say that there is neither an edge or center to the universe, yet we live in a finite universe. I understand how our universe can be finite yet have no edges due to the curvature of the universe, but I can't understand how it doesn't have a center. Space must be being curved around...
  10. S

    Solving Geometry Problem: Disparity in Terms of a, D, d, e, & f

    Homework Statement Disparity is defined as \delta = \alpha - \beta. Find \delta in terms of interocular distance a, viewing distance D and d, e and f. http://img220.imageshack.us/img220/7576/43519392.jpg The Attempt at a Solution I'm not getting anywhere. Any tips to get me started?
  11. P

    Introductory Differential Geometry Book With Lots of Intuition

    So I took an analysis class which covered chapters 9 and 10 of Rudin's PMA, for those of you who don't know that's multivariable analysis and differential forms, and I have taken a course in vector calculus but never a proper course on differential geometry. Thus my introduction to the subject...
  12. J

    Determining Riemann surface geometry of algebraic functions

    Hi, given the algebraic function: f(z,w)=a_n(z)w^n+a_{n-1}(z)w^{n-1}+\cdots+a_0(z)=0 how can I determine the geometry of it's underlying Riemann surfaces? For example, here's a contrived example: f(z,w)=(w-1)(w-2)^2(w-3)^3-z=0 That one has a single sheet manifold, a double-sheet...
  13. F

    Absolutely clueless on how to do this Geometry Help

    Homework Statement There are three problems based on the following diagram. You have a triangle on the cartesian plane with each corner having the coordinates (-a, 0) (a,0) (b,c) Find the coordinates (in terms of a,b,c) of the point where all three perpendicular bisectors of the...
  14. M

    Can anyone recommend a good geometry book?

    Can anyone recommend a good geometry book?
  15. X

    Geometry Help: Solving Lagrangian Problem

    This is a Lagrangian problem, I am posting it here in introductory physics because what I need help with isn't in Lagrangian mechanics, but rather geometry. http://img97.imageshack.us/img97/7504/what3.png I am confused as how they got those relations for x and y. I have tried to make...
  16. Elroch

    The effect of external masses on internal black hole geometry

    Suppose you have the simplest type of black hole - time independent, no angular momentum or charge, Schwarzschild solution, then you modify the situation by adding a stationary mass outside the event horizon (I imagined lowering this slowly on an idealised string). The question is, does this...
  17. Z

    Lecture notes in The Differential geometry of Gauge theory?

    Hi all , How can I find lecture notes on ArXiv ? I was looking for lecture notes on Yang-mills theories treated in the language of differential geometry but didn't succeed till now . Can some one recommend me some good resource for it?
  18. J

    Laplace equation in rectangular geometry

    [/itex][/itex]Homework Statement A battery consists of a cube of side L filled with fluid of conductivity s. The electrodes in the battery consist of two plates on the base at y = 0, one grounded and one at potential V = 12 Volts. The other sides of the battery casing are not conductive...
  19. N

    Solve Arrow Head Geometry Question with L1, L2 & L3

    Homework Statement I have this arrow head geometry question (Please see diagram). I know L1, L2 and L3, angle B and the constant k (notice how the corner angle is equal to k * t2). I don't know t1 and t2. I'm pretty sure I have enough constraints, I'm just having trouble finding the right...
  20. S

    Inequality with Circle and Triangle in Euclidean Geometry

    Homework Statement Please see below... Homework Equations Please see below... The Attempt at a Solution Hi. This question is on geometry with circle and triangle. I am stuck only on 2 parts of the solution and not the whole solution... Thank you...
  21. N

    Serial Link chain with constrained geometry

    I have a three link revolute manipulator at the origin. I know all the link lengths. The joint angle for the third link is coupled to the second such that Theta3 = k*Theta2. I want to determine the joint angles (thetas) of the manipulator given that the third link should lie on a line an angle...
  22. P

    Proving Quadrilateral PQRS is a Parallelogram

    Recently, I bought a book and found a strange question : In the given figure, PQRS is a quadrilateral. PO and QO are bisectors of angle P and angle Q respectively, then prove that angle QOP = 1/2 (angle R + angle S) I made several attempts to get the solution but failed. I guess, we need...
  23. E

    Two linear algebra questions - Vector geometry

    Homework Statement http://184.154.165.18/~devilthe/uploads/1321855187.pngHomework Equations No idea.The Attempt at a Solution Alright...so really no idea what to do here...never did any examples like this in class and have scoured over my notes for 2 hours now trying to figure this out...and...
  24. A

    Geometry & Physics: How Much Math Involves Geometry?

    I did bad in geometry my sophomore yr of high school. Sr. Year I plan on taking physics. How much of physics math deals with geometry?
  25. V

    Basic questions of complex number's geometry?

    Homework Statement (z' represent conjugate of complex number z,i is iota =sqrt(-1)) (1)find the locus of z. |z|2+4z'=0 (2)|z1|=1, |z2|=2, then find the value of |z1-z2|2+|z1+z2|2 (3)z=(k+3)+i[sqrt(3-k2)] for all real k. find locus of z Homework Equations |z|2=z.z' The Attempt at a...
  26. G

    Are there any good books on logic and plane geometry?

    Hello, After reading both How to Prove It: A Structured Approach - By Daniel J Velleman, and one of the Lost Feynman Lectures on Planetary Orbits, I'm wondering if anyone could suggest to me any good books they've read (or heard about) pertaining to logic (paired with analysis), or plane...
  27. jaumzaum

    Does anyone know about any good (advanced) geometry book?

    Hi, recently I've tried to find a good sintetic geometry book with both theory and exercises. Many people said well about this one https://www.amazon.com/dp/0486458059/?tag=pfamazon01-20 College Geometry. I've bought it and I've got so disappointed. I want a book that has exercises...
  28. S

    Geometry Fields in Laymens Terms

    The concept of describing something in layman's terms has come into wide use in the English speaking world. To put something in layman's terms is to describe a complex or technical issue using words and terms that the average individual (someone without professional training in the subject area)...
  29. S

    Calculus and Geometry with a Cubic Function and Straight Line

    Homework Statement I am asking about part iv). [PLAIN]http://img715.imageshack.us/img715/7977/113ivb.jpg Homework Equations I guess they would be the ones in the earlier parts... The Attempt at a Solution In the given fact, I think x^3 - x - m(x - a) distance from the...
  30. X

    Geometry: problem with defining the vertices of a tunnel around a given path

    I'm trying to create some kind of demo that rushes through a tunnel. I have made a random path generator that creates smooth looking paths in 3D space (just some 3D points) Now I would like to create polies that form a tunnel around that path. To give an example, let us assume that the path...
  31. S

    What are the most beautiful fields of geometry?

    Hello , I have something called Asperger's Syndrome and I would like to find a narrow topic or highly specialized field to study in the future as an Aspiring pure mathematician. But I have little or no experience in Mathematics , that's why I'm asking this question. I obsess about geometrical...
  32. T

    Vectors and the Geometry of Space

    Line 1 and line 2 are given by equation 1 and 2. Point A has coordinates (xo, yo, zo). Find the equation of line 3 which goes through A and crosses L1 and L2.
  33. M

    Proving AD Bisects Angle CAE in Triangle ABC

    Homework Statement Given a triangle ABC with BC = 2AB. D and E are the midpoints of BC and BD respectively. Show that AD bisects angle CAE. Homework Equations The Attempt at a Solution Let AB= x, so DC= AB= x and ED = x/2. If AD bisects angle CAE, then AC/AE = DC/DE...
  34. B

    Fractal Geometry: Uses, Math & Fascinating Patterns

    The very first time I ever heard about fractals was in my junior year in high school in my Algebra II class when we were studying complex numbers. I was fascinated by these wonderous objects and I've had many questions about them ever since. Though two of my main questions have always been...
  35. B

    Euclidian geometry: Construct circle trough point on angle bisector where

    Homework Statement This is part from a larger construction, but I realized if i can construct this, i can do the larger construction. All ofcourse with ruler and compass. I have been given an angle with its bisector and a point on that bisector. I have to construct a circle trough that point...
  36. AGNuke

    Co-Ordinate Geometry - Find P for |PA - PB| is maximum

    The co-ordinates of a point P on the line 2x - y + 5 = 0 such that |PA - PB| is maximum, where A is (4,-2) and B is (2, -4) will be: A) (11, 27) B) (-11, -17) (Answer) C) (-11, 17) (Eliminated since it does not lie on the given line) D) (0, 5) Honest speaking, I don't know what to do in...
  37. S

    Suggestions for a physics masters dissertation in geometry.

    Hi, I am currently studying for a one year postgrad MSc in Theoretical Physics. In my undergraduate physics degree, my dissertation was on general relativity, so I got a taste of differential geometry and manifolds which I really enjoyed. At the moment I'm currently attending lectures...
  38. V

    Geometry Proof (Circles and Chords)

    Hey all. At my school we have these things called "Real Problems" that we get every 3-4 weeks. This time it's about proofs. I have an A- in the class, so I got the difficult one with 4 very difficult (IMO) proofs. I have NO idea where to start on this..I have drawn it out for you. All help is...
  39. R

    Simple trigonometry / geometry question. Diagram included

    Hey all, BACKGROUND: (please note that knowledge of this is not necessary): I'm currently writing a javascript application using vectors (with jquery and raphaeljs) that enables me to rotate custom text (using font.js file, not normal fonts). However, due to a bug in the new version of raphael...
  40. sankalpmittal

    Geometry Problem: Finding the Sum of Perpendiculars in an Equilateral Triangle

    Homework Statement Let ABC be an equilateral triangle with side 10 cm and let P be a point inside the triangle at a distance of 2 cm from the side AB. Given --> AB = BC = CA = 10cm and PD = 2 cm. If PD, PE, PF are the perpendiculars to the three sides, find out the sum, PD + PE + PF. Here is...
  41. M

    Do intersecting circles always have equal angles at the circumference?

    I was wondering if the common chord of two intersecting circles subtends an equal angle in both circles at the circumference (in no special cases i.e different radii circles etc) If not, are there any special case(s) where this would work, making these two triangles similar or ABDC is a...
  42. S

    Algebraic Geometry Question - on ideals of algebraic sets

    Hello everyone, I was wondering if I could get some advice for the following problem: I have two algebraic sets X, X', i.e. X = V(J), Y = V(J'), and let I(X),I(Y) be the ideals of these sets, i.e. I(X) ={x \in X | f(x) = 0 for all x \in X}. I am trying to show that I(X \cap Y) is not always...
  43. O

    Understanding Tangents in Analytic Geometry

    Okay so I am reading a book on analytic geometry because my algebra class is starting to really bore me, and I ran across this: slope = m = -1/2 (easy enouph) but then it states "since the slope is the tangent of the angle of inclination θ, we have: tan θ = -1/2 okay so I guess my...
  44. U

    What exactly is differential geometry?

    Hello. I'm new here and I'm not sure if I should post this topic here or in general math, or anywhere else. Feel free to move the topic elsewhere if needed. Just a bit of explanation first. I'm not from USA (so forgive any grammar errors) and I don't understand completely your academic...
  45. I

    Usefulness of Differential Geometry?

    My university is offering a Differential Geometry course next semester and while I am interested in the subject, I do not plan to take the class unless it has practical use for me. I have no interest in doing theoretical work. Does differential geometry serve any use to applied physics/engineering?
  46. J

    A relatively easy differential geometry question concerning principle curvatures

    Homework Statement Show the principal curvatures on x sin z - y cos z = 0 are +-1/(1 + x^2 + y^2)
  47. N

    When two spheres intervine - very hard 3d geometry and vectors problem

    Homework Statement Sphere with P as centre has equation (x-5)^2 + (y-9)^2 + z^2 -100 = 0 Sphere with Q as centre has equation (x-1)^2 + (y+3)^2 + (z-3)^2 -49 =0 These spheres intervine with each other. Find the surface area of the object limited by the two spheres. The Attempt at a Solution...
  48. O

    Question about Geometry vs. Calculus in Physics Problem

    Okay, I'm not asking how to find the solution to this problem. I already found the solution they were looking for. The thing that confuses me is that I got two different solutions using two methods that should have given me the same answer. Could someone show me what I did wrong? Homework...
  49. O

    Projections in Geometry (Question)

    nevermind i figured it out
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