Geometric Definition and 813 Threads

  1. G

    MHB Arithmetic string equal to the geometric string, count x

    Let x1, ..., x25 be such positive integers that x1⋅x2⋅ ... ⋅x25 = x1 + x2 + ... + x25. What is the maximum possible value of the largest of numbers x1, x2, ..., x25?
  2. F

    Geometric sum using complex numbers

    Solution to the problem tells us that ##S_5 + i S_6## is the sum of the terms of a geometric sequence and thus the solutions should be : $$S_5 = \frac{\sin( (n+1) x)}{\cos^n(x) \sin(x)},\,\,\,\, S_6 = \frac{\cos^{n+1}(x) - \cos((n+1)x)}{\cos^n(x) \sin(x)} , x \notin \frac{\pi}{2} \mathbb{Z}$$...
  3. U

    Finding the sum of a geometric series

    I'm using the sum of a geometric series formula, but I'm not sure how to find the ratio, r. The n is confusing me. The solution is below, but I'm having trouble with the penultimate step.
  4. S

    I Show isometry and find geometric meaning

    The matrix ##A## in question is ##\dfrac{1}{3} \left(\begin{array}{rrr} -2 & 1 & -2 \\ -2 & -2 & 1 \\ 1 & -2 & -2 \end{array}\right)## One can easily verify that ##AA^t=I##, hence an isometry. To find its geometric meaning, one can proceed to find ##U=\text{ker} \ (F-I)=\text{ker} \...
  5. S

    Understanding Sum to Infinity in Geometric Progression

    My question is Why is the sum to infinity used as opposed to Sum to n? and How can I deduce that the sum to infinity must be used from the question?Total Distance = h + 2*Sum of Geometric progression (to infinity) h + 2*h/3 / 1-1/3 h + 2h/3 *3/2 = h + h = 2h At first I did sum to infinity...
  6. christang_1023

    I How to understand this property of Geometric Distribution

    There is a property to geometric distribution, $$\text{Geometric distribution } Pr(x=n+k|x>n)=P(k)$$. I understand it in such a way: ##X## is independent, that's to say after there are ##(n+k-1)## successive failures, ##k## additional trials performed afterward won't be impacted, so these ##k##...
  7. Hiero

    I Geometric Algebra: Rejection of one blade in another

    Let the (multi-vector valued) “inner product” between a j-vector U and a k-vector B be defined as the (k-j) grade part of the geometric product UB, (a.k.a. “left contraction”) that is, $$U\cdot B := <UB>_{k-j}$$ (0 when j > k) as is done in Alan Macdonald’s book “Linear and Geometric Algebra.”...
  8. S

    I What is the geometric plan for ALMA?

    I was watching a TV show about these telescopes being transported up to a high plateau in Chile. Looking at the Wiki page, it seems that they are to be arranged in random geometry, although maybe there is some pattern to the arrangement. Does being in some pattern - or being in a random...
  9. ali PMPAINT

    A geometric proof (minimizing the length of two lines in a rectangle)

    So, I know it can be proven using calculus, but I need the geometric one. So, I got that ^c=^d and therefor, the amount of increment in one of a, is equal to the other(^e=^b). (Also 0<a+b<Pi/2) And AP'=BP'=BD/sin(a) and BP=BD/sin(a+b) and AP=BD/sin(a-b). AP'+BP'=2AP'=2BD/sin(a) and...
  10. Math Amateur

    MHB Convergence of Geometric Series .... Sohrab, Proposition 2.3.8 .... ....

    I am reading Houshang H. Sohrab's book: "Basic Real Analysis" (Second Edition). I am focused on Chapter 2: Sequences and Series of Real Numbers ... ... I need help with an aspect of the proof of Proposition 2.3.8 ... Proposition 2.3.8 and its proof read as follows: In the above proof by...
  11. E

    Why do snowflakes freeze into complex geometric patterns?

    Why do snowflakes freeze into complex geometric patterns?
  12. M

    I Geometric meaning of reversing the limits of an integral

    With respect to operations, I understand why an integral is multiplied by -1 when its limits reversed. But integral is geometrically an area so reversing the limits would not be able to change neither how large is the area nor the shape of the area. Would you please explain changing the limits...
  13. WMDhamnekar

    MHB Find Common Difference of A.P. Given G.P. & Logarithms

    If a,b, c, are in G.P and $\log_ba, \log_cb,\log_ac$ are in A.P. I want to find the common difference of A.P. Answer: After doing some computations, I stuck here. $\frac{2(\log a+\log r)}{\log a+2\log r}=\frac{2(\log a)^2+3\log r\log a +2(\log r)^2}{(\log a)^2+\log r\log a}$ How to proceed...
  14. Demystifier

    Insights The Sum of Geometric Series from Probability Theory - Comments

    Greg Bernhardt submitted a new blog post The Sum of Geometric Series from Probability Theory Continue reading the Original Blog Post.
  15. E

    I Deriving reduction formula in Geometric Algebra

    Hi, I am trying to learn Geometric Algebra by going through the book "New Foundations for Classical Mechanics" by David Hestenes. I was reading the part about reduction formula (shown below) but couldn't get the result the shown in the book. Can someone show me how iterating (1.15) gives the...
  16. P

    I Grover algorithm geometric interpretation

    Good day everybody, I'm currently working on the Grover algorithm. You can also illustrate this process geometrically and that's exactly what I have a question for. In my literary literature one obtains a uniform superposition by applying the Hadamard transformation to N-qubits. So far that's...
  17. diegzumillo

    A What is geometric group theory and how does it relate to different geometries?

    Hey all I previously asked about some math structure fulfilling some requirements and didn't get much out of it ( Graph or lattice topology discretization ). It was a vague question, granted. Anyway, I seem to have stumbled upon something interesting called geometric group theory. It looks...
  18. H

    MHB Do Pi and Geometric Shapes Coexist?

    (1) Is there a pi in ellipse entity?Why not or yes? (2) Is there a pi in polygons entities (e.g square)? not or yes? (3) If there is pi in some geometries and other not - What is the reason to that? (4) How cloud I know that are no hidden formula of pi in a square figure that the expression in...
  19. Math Amateur

    MHB Geometric Interpretation of k-Forms from H&H's Vector Calculus

    I am reading the book: "Vector Calculus, Linear Algebra and Differential Forms" (Fourth Edition) by John H Hubbard and Barbara Burke Hubbard. I am currently focused on Chapter 6: Forms and Vector Calculus ... I need some help in order to understand some notes by H&H following Figure 6.1.6 ...
  20. Beth N

    Geometric optics: Thin lense equation

    Homework Statement A 2.0-cm-tall candle flame is 2.0 m from a wall. You happen to have a lens with a focal length of 32 cm. How many places can you put the lens to form a well-focused image of the candle flame on the wall? For each location, what are the height and orientation of the image...
  21. A

    Geometric Law of Probability with Dice

    Homework Statement We have a normal 6 sided dice marked from 1 to 6. There is an equal chance to get each number at every roll. Let's put 1&2 as A type, 3&4 as B type and 5&6 as C type. We roll the dice over and over until we get a number of every type. Let X be the number of rolls. We are...
  22. L

    Geometric Optics Approximation - validity

    How is the "geometric optics approximation" exactly defined? Given all the source of visible radiation's parameters, all the apparatus, instruments, screen, etc, specifications, how can I know if, e. g. there will be diffraction, interference or other wave properties or if I'll be able to...
  23. R

    I Geometric mean versus arithmetic mean

    The Beer-Lambert law gives the intensity of monochromatic light as a function of depth ##z## in the form of an exponential attenuation: $$I(z)=I_{0}e^{-\gamma z},$$ where ##\gamma## is the wavelength-dependent attenuation coefficient. However, if two different wavelengths are present...
  24. Mr Davis 97

    If lim a_n = L, then the geometric mean converges to L

    Homework Statement Let ##\{a_n\}## be a sequence of positive numbers such that ##\lim_{n\to\infty} a_n = L##. Prove that $$\lim_{n\to\infty}(a_1\cdots a_n)^{1/n} = L$$ Homework EquationsThe Attempt at a Solution Let ##\epsilon > 0##. There exists ##N\in\mathbb{N}## such that if ##n\ge N## then...
  25. talk2dream

    I You cannot differentiate a geometric figure?

    I was reading a different post, https://www.physicsforums.com/threads/differntiating-a-circle.279719/#post-2003287 and was doing great... guys, thanks so much for this forum! HallsofIvy posted "1: You titled this "differentiation of a circle" which makes no sense. You cannot differentiate a...
  26. D

    Help with Geometric Dimensioning and Tolerancing....

    Hi all, I am trying to teach myself GD&T from a textbook (Fundamentals of Geometric Dimensioning and Tolerancing - Krulikowski) and would like some feedback on a drawing I've created, please see attached. Any help/criticism would be greatly appreciated. Regards, Doc
  27. Robin04

    What is the transformation function for reflecting points on a complex plane?

    Homework Statement Let's call the axis of the ##z## complex plain ##x## and ##y##, so a general point can be written as ##z=x+iy##. Reflect the points of the complex plain so that the mirror line of the transformation is a line parallel to the vector ##v## and it passes trough the point ##u##...
  28. J

    MHB Real Analysis, Sequences in relation to Geometric Series and their sums

    I will state the problem below. I don't quite understand what I am needing to show. Could someone point me in the right direction? I would greatly appreciate it. Problem: Let p be a natural number greater than 1, and x a real number, 0<x<1. Show that there is a sequence $(a_n)$ of integers...
  29. Robin04

    Triangle determined by arithmetic and geometric sequences

    Homework Statement Determine the triangles where the sides are consecutive elements of a geometric sequence and the angles are consecutive elements of an arithmetic sequence. Homework Equations The Attempt at a Solution I don't really know how to approach this problem, what the solution would...
  30. H

    B Geometric meaning of signs in multiplications

    What does 1/-1 (one divided by minus one) mean? What does -1 X -1 (minus one multiplied by minus one) mean? What are the best graphic representations of multiplication and division?
  31. W

    B Fourier Transform: Geometric Interpretation?

    Hi, outside the mathematical proof that shows that sines of different frequency are orthogonal... is there geometric interpretation/picture of this phenomena?
  32. alijan kk

    Geometric Sequence: Find X, 5th Term

    Homework Statement The first three terms of a GP are X,X+2,X+3. The value of X and the fifth term is.[/B] (a)-4,1/4 (b)4,1/4 (c)2,1/4 (d)-2,-1/4 Homework EquationsThe Attempt at a Solution (x+2/x)=(x+3)/(x+2) (x+2)2=x2+3x x2+2x+4=x2+3x x=4 so i think r=(x+2)/x putting x=4 r=3/2 also...
  33. S

    How Do You Calculate Geometric Buckling for Cylinders and Spheres?

    Mentor note: Thread moved from a different forum section, so missing the homework template. I'm very confused about the attached questions on geometric buckling of a cylinder and a sphere. For this question I'm not given a value for the extrapolated distances (for R' and H') so I simply put the...
  34. Gene Naden

    Geometric Version of Maxwell Equation related to Tensor Dual

    Homework Statement From Misner, Thorne and Wheeler's text Gravitation (MTW), exercise 3.15: Show that, if F is the EM field tensor, then ##\nabla \cdot *F## is a geometric, frame-independent version of the Maxwell equation...
  35. B

    MHB Jack's Rhombus Ring Pattern: A Unique Geometric Design

    Jack draws rings of rhombuses about a common centre point. All rhombuses have the same side length. Rhombuses in the first, or inner, ring are all identical. Each rhombus has a vertex at the centre and each of its sides that meet at the centre is shared with another rhombus. They all have the...
  36. R

    I Geometric Meaning of Complex Null Vector in Newman-Penrose Formalism

    Reading Chandrasekhar's The mathematical theory of black holes, I reached the point in which the Newman-Penrose GR formalism is explained. Actually I'm able to grasp and understand the usage of null tetrads in GR, but The null tetrads used in this formalism, are very special, since are made by...
  37. C

    MHB Geometric Series: Find Sum of Infinity - 9-32-n

    Given that the sum of the first n terms of series, s, is 9-32-n Find the sum of infinity of s. Do I use the formula S\infty = \frac{a}{1-r}?
  38. C

    MHB Solve Geometric Series: Find n from s=9-32-n

    Given that the sum of the first n terms of series, s, is 9-32-n show that the s is a geometric progression. Do I use the formula an = ar n-1? And if so, how do I apply it?
  39. Vital

    Geometric mean application in finance ratio question

    Homework Statement Hello. There is a financial metric called time weighted rate of return, which is computed using the following formula: 1) if we compute daily returns, or other returns within a year: r tw = (1+r1) x (1+r2) x...x (1+r nth year), where r tw is the time weighted rate of return...
  40. C

    MHB The proof of the infinite geometric sum

    Dear Everybody, I need some help with find M in the definition of the convergence for infinite series. The question ask, Prove that for $-1<r<1$, we have $\sum_{n=0}^{\infty} r^n=\frac{1}{1-r}$. Work: Let $\sum_{n=0}^{k} r^n=S_k$. Let $\varepsilon>0$, we must an $M\in\Bbb{N}$ such that $k\ge...
  41. M

    MHB Geometric Sequence find the 23rd term.

    A geometric sequence has an initial value of 25 and a common ratio of 1.8. Write a function to represent this sequence . Find the 23rd term. My Effort: The needed function is a_n = a_1•r^(n-1), n is the 23rd term, r is the common ratio and a_1 is the initial value. a_23 = 25•(1.8)^(23 - 1)...
  42. anemone

    MHB Finding $\theta$ in a Geometric Diagram

    Solve for $\theta$ in the diagram below.
  43. shintashi

    B What is the name of this triangular geometric shape?

    I used to think it was called Zeno's tower, but then realized I probably called it that because it reminded me of his paradox. I have been unable to find this shape on the internet, although I saw a small steel tower outside Stonybrook using this geometry. I have attached an image of the basic...
  44. T

    I Geometric intuition of a rank formula

    I am trying to understand the geometric intuition of the above equation. ##\rho(\tau)## represents the rank of the linear transformation ##\tau## and likewise for ##\rho(\tau\sigma)##. ##Im(\sigma)## means the image of the linear transformation ##\sigma## and lastly, ##K(\tau)## is the kernel of...
  45. C

    I Is there a geometric interpretation of orthogonal functions?

    Hi all. So to start I'll say I'm just dealing with functions of a real variable. In my linear algebra courses one thing was drilled into my head: "Algebraic invariants are geometric objects" So with that in mind, is there any geometric connection between two orthoganal functions on some...
  46. Y

    MHB Calculating Geometric Probability on a Round Table

    Hello all, I have a question related to geometric probability. I think I solved it, but not sure, would appreciate your opinion. We are given a round table with a radius of 50cm. At the center of this table there is another circle, with a radius of 10cm. A coin with a radius of 1cm is thrown...
  47. X

    I Is this a compound angle? What's the geometric meaning?

    β is vehicle sideslip (angle between velocity and vehicle forward vector) ψ the angle between the trajectory tangent and vehicle forward vector. I have this equation that says Vx * k * (cos ψ - tan β * sin ψ) where k is trajectory...
  48. yeshuamo

    Variable of integration in geometric phase calculation

    Homework Statement Calculate the geometric phase change when the infinite square well expands adiabatically from width w1 to w2.Homework Equations Geometric phase: \gamma_n(t) = i \int_{R_i}^{R_f} \Bigg< \psi_n \Bigg | \frac{\partial \psi_n}{\partial R} \Bigg > dR Infinite square well wave...
  49. A

    Geometric optics (near point problem)

    Homework Statement A person with a near point of 100 cm , but excellent distant vision, normally wears corrective glasses. But he loses them while traveling. Fortunately, he has his old pair as a spare. If the lenses of the old pair have a power of +2.55 diopters , what is his near point...
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