What is Line: Definition and 1000 Discussions

Líně is a municipality and village in Plzeň-North District in the Plzeň Region of the Czech Republic. It has about 2,800 inhabitants. Líně lies approximately 11 kilometres (7 mi) south-west of Plzeň and 95 km (59 mi) south-west of Prague.

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  1. Math Amateur

    MHB Parametrizatrion of a Straight Line Segment in C - Simple Issue

    I am reading Mathews and Howell's book: Complex Analysis for Mathematics and Engineering. I am currently reading Section 1.6 - "The Topology of Complex Numbers". I have a problem with an aspect of Example 1.22 on page 38. My problem is a simple one related to algebraic manipulation of a couple...
  2. N

    Line Integral Evaluation

    Homework Statement Evaluate the line integral ∫^{(1,0)}_{(0,1)} (x^2-y)dx + (y^2+x)dy along (a) a straight line from (0,1) to (1,2); (b) the parabola x=t, y=t2 + 1; (c) straight lines from (0,1) to (1,1) and then from (1,1) to (1,2). Homework Equations Equation of line: y = mx + c The Attempt...
  3. P

    Using Green's Theorem for Solving Line Integrals

    Homework Statement i have this problem and need your help. I tried to solve the first 2 question but don't know ho to solve the third one
  4. C

    Binomial Distribution for a person walking in straight line

    Homework Statement Can I measure the probability of a person being at a certain end location after n steps using the binomial distribution if, probability student goes x=x+3 is 0 <= p <0.5 , x=x-1 is 0<= 0.5 p <1.Homework Equations x=x+3 is 0 <= p <0.5 x=x-1 is 0<= 0.5 p <1 The Attempt at a...
  5. J

    What does this line of Isaac Newton's rap video mean?

    Go to 1:24 of this video: He recalls some integral he wrote at a young age: " ... times the sixty-fourth power of ... what?" and looks confused. At 1:44 Neil Degrasse Tyson says, "By the way, the answer to your little calculation is i." Can someone explain the historical reference to me...
  6. T

    Flow line in conservative vector field

    Homework Statement Recall that a flow line, c(t), of a vector field F has c'(t)=F(c(t)) at all times t. Show all work below. a.) Let c(t) be the flow line of a particle moving in a conservative force field F=-grad(f), where f:R^3->R, f(x,y,z) >=0 for all (x,y,z), represents the potential...
  7. M

    Find a point on the line closest to another point

    Homework Statement (2 part problem) a) A plane passes through the point P(3,1,4) and is orthogona to the line (x-1)/2 = (2-y)/-7 = z-3 b) Find the point on the line closest to point (3,1,4) Homework Equations Symmetric equation --> (x-x1)/t = (y-y1)/t = (z-z1)/t ( anyway i think that's what...
  8. PcumP_Ravenclaw

    Doubt about condition solutions of complex line equation

    Dear All, Please help me clear some doubts about Theorem 3.3.1 in the 1st attachment. The condition ## |a| = |b| ## has only 8 cases right? ## { x+iy. x - iy, -x + iy, -x - iy, y + ix, y - ix, -y + ix, -y - ix } ## so for the condition ## |a| = |b| ## and ## b \bar c = \bar a c...
  9. Amy Marie

    Evaluating Line Integral with Green's Theorum

    Homework Statement Use Green's Theorum to evaluate the line integral ∫c (x^2)y dx, where c is the unit circle centered at the origin. Homework EquationsThe Attempt at a Solution Taking the partial derivative with respect to y and subtracting it from zero(I'm taking the dy in the original...
  10. CopyOfA

    Potenial inside Wedge due to Line Charge

    Homework Statement We are given a wedge configuration with three sections. There are two conducting planes held at zero potential that make an angle of ##2\beta## with each other. They are connected by a portion of a conducting cylinder with radius ##a##. An infinite uniform line charge of...
  11. T

    Why Does the Hydrogen Spectrum Lack X-ray Frequencies?

    Why line spectrum of hydrogen includes no X-ray frequencies?
  12. dwn

    Line Integral of f(x,y,z): Exploring the Answer

    Homework Statement Find the line integral of f(x,y,z) = x+y+z over the straight-line segment from (1,2,3) to (0,-1,1). Homework Equations ∫ f(x,y,z)ds = ∫ f(g(t), h(t), k(t)) |v(t)| dt The Attempt at a Solution I arrived at the correct solution, but I'd like some clarity on the result...
  13. L

    Parametrics tangent line with point given

    Homework Statement I understand the setup for finding the slope, but always get confused whether I've fully simplified when trig identities get involved. [/B] Homework Equations My dy/dx is [/B] 4sin(θ)cos(θ) -2csc2(θ) which I simplified to just (-2sin(θ)cos(θ))/(csc2(θ) Does that...
  14. N

    Line integral over a given curve C

    Homework Statement Evaluate the line integral over the curve http://webwork.math.ttu.edu/webwork2_files/tmp/equations/33/92ca0e3b907f876e5a974ad1457d1f1.png from to http://webwork.math.ttu.edu/webwork2_files/tmp/equations/6f/bccf9dd59b9c22450c590a042bb77d1.png . ∫-ydx+3xdy (over the curve C)...
  15. R

    Simple thought Experiment, Straight Line between 2 Distant Points

    (from my limited understanding) In our observable universe a photon could travel say, 5 billion light years in a straight line if unperturbed. Call the points X and Y traveling down-up. If point X was moved one Planck length to the left, would it still be able to travel exactly to point Y?
  16. I

    MATLAB Line following Matlab Code. How to Start?

    So we're using NXT 2.0 and MATLAB to program a robot to follow a white line through a maze. I'm using a light sensor, color sensor and an ultrasonic sensor in the process. Any programming/Coding ideas of how i should start? This is the maze...
  17. R

    Finding a point on a line closest to a point in space

    Homework Statement Let \Delta be a line and A a point in space. [itex ] B [/itex] is a point on \Delta ans H is a point on \Delta such that \newcommand{\vect}[1]{\vec{#1}} \vec{AH} \perp \Delta . a) Show that \| \vec{AH} \| \leq \| \vec{AB} \| (a geometric reasoning should be used)...
  18. P

    Power Transmission Line and Transformer Parameters

    Hi, I was wondering if it would be possible for someone to help me clarify a few things regarding transmission lines and transformers? For a Power Transmission line, what exactly is the mutual coupling between phases of a 3 phase line? Is this the same as the shunt capacitance and if not...
  19. P

    3 phase transmission line mutual coupling

    Hi, if I simulate a three phase transmission line operating with a fault across two of the phases, would the mutual coupling have any effect on the current through each of the lines, as I have calculated the fault current values using symmetrical component analysis and the values are...
  20. M

    The angle between a line and a plane

    Homework Statement In Exercises 45-46, show that the plane and line with the given equations intersect, and then find the acute angle of intersection between them. 45. The plane given by x + y + 2z = 0 and the line given by x = 2 + t y = 1 - 2t z = 3 + t Verbatim from Poole - Linear Algebra: A...
  21. avito009

    Why would Earth move in straight line without sun's gravity?

    If there was no Sun then the Earth would move in a straight line with constant velocity. This is because the space has vacuum and there is no friction in space. This is because if you observe on Earth where there is friction we need to apply force against this friction. But in space there is...
  22. E

    Calculating Length of Line cf: A Math Problem Explained

    In the problem attached, why is the integral become just the length of line cf?
  23. S

    Calculating Phase & Line Current

    < Mentor Note -- thread moved from EE to the Homework Help forums > I'm studying for a Level 3 Diploma in Electro technical science. My tutor had a hard time teaching me what I need to know in order to answer this question; Calculate the phase and line current when three resistors each having...
  24. C

    The Fundamental Theorem for Line Integrals

    Homework Statement Determine whether or not f(x,y) is a conservative vector field. f(x,y) = <-3e^(-3x)sin(-3y),-3e^(-3x)cos(-3y) > If F is a conservative fector field find F = gradient of f Homework Equations N/A The Attempt at a Solution Fx = -3e^(-3x)(-3)cos(-3y) Fy =...
  25. J

    Pulling Conductor - Transmission Line

    I need to figure out if my companies pulling equipment can handle a 795 drake conductor (about 1 lb/ft) double bundled (times 2). The pulling equipment has a safe working load of 4000 lbs. We are pulling it across 16 spans with a average span of 674 feet. the towers are 115' tall. Max sag...
  26. C

    Prove two line elements represent the same space/plane

    Homework Statement I've been given the line element given below in the relevant equations section and I need to prove that the space it represents is just the same as the 2-D Euclidean plane. Homework Equations ds^2 = a^2 \frac{d\eta ^2 }{cosh^4(\eta)} + a^2 tanh^2(\eta) d\theta ^2 Where...
  27. M

    LaTeX Create a vertical line in Latex

    Hi PF! I am very new with Latex and was building a resume using a downloaded template. What I would like to do is create a vertical line down the page. Can anyone help? The line of code that seems to create a horizontal line is...
  28. AwesomeTrains

    Line Integral - Stokes theorem

    Homework Statement Hello I was given the vector field: \vec A (\vec r) =(−y(x^2+y^2),x(x^2+y^2),xyz) and had to calculate the line integral \oint \vec A \cdot d \vec r over a circle centered at the origin in the xy-plane, with radius R , by using the theorem of Stokes. Another thing, when...
  29. P

    Line-Line Fault Circuit: Parallel or Series?

    Hi, When calculating a line-line fault, I understand that the Positive and Negative Phase Sequence networks are placed in parallel with each other as shown in the first attached image, and that the zero phase sequence is excluded. Although this is connected in parallel, does it not produce a...
  30. ilovescience85

    How Do You Calculate Sensor Non-Linearity from a Polynomial Equation?

    Homework Statement The input range of a particular sensor is from 0-6 units and it's output is modeled by the equation O = ƒ(I) = 1+2I+0.005I^2-0.00833I^3 Ideally the output should be relate to the input by the straight line equation (ISL) if the form O=kI+a A) give the law if the ideal...
  31. ChimM

    Geometry - Chord of a circle

    Homework Statement Attached here is a diagram. My questions are, how to compute for the value of the chord? How to compute for the value of the tangential line? Please help.. Thank you in advance.
  32. Stoney Pete

    Is the Real Number Line Actually Infinite?

    Hi guys, Here is a little puzzle I have been wondering about. I can't solve it, perhaps you can help. We know there are infinitely many real numbers on the number line. Indeed, already between 0 and 1 there are infinitely many real numbers. So if a real number is a point on the number line...
  33. G

    Solving a Line Integral Problem: Struggling for the Right Answer

    Hi everyone. I ran into a minor problem while trying to solve a problem on line integral. I suspect this question to be very straight-forward as it gave the parametric equations of the curve C. However, I am still unable to get the answer for some reason. May I have someone to point out where I...
  34. PhysicsKid0123

    Confused about force and work in 3 Dimensions. Line integrals.

    So I am kind of confused about the role of force when calculating work. Specifically, when defining work using a line integral. There is a paragraph in my calculus book that is really throwing me off and its really bugging me so much I can't continue reading unless I fully understand what's...
  35. E

    MHB How Do You Find the Point Where a Tangent Equals a Secant Slope?

    Given the function f(x) = 3x / (x - 2), determine the coordinates of a point on f(x) for 3 < x < 6 where the slope of the tangent line is equal to the slope of the secant line passing through A(3, 9) and B(6, 9/2). So I found that the slope of the secant line is -1.5 (therefore slope of tangent...
  36. S

    Distance between line segments: near parallel case TOO

    Does anyone know a good algorithm for calculating the closest points/distance between two line segments? I use some pretty general code: http://geomalgorithms.com/a07-_distance.html which works in most cases but fails horribly when line segments are nearly parallel. I've been messing with the...
  37. T

    MHB At what point on the curve is there a tangent line parallel to the line

    At what point on the curve $$y = e^x$$ is the tangent line parallel to the line $$y = 2x$$ The derivative of y is $$\frac{dy}{dx} = e^x$$ But I'm unsure how to proceed from here.
  38. G

    Line operations on matrix products

    Can I perform line operations on a matrix product? For example the matrix product ABC and I know that A and C are invertible, can I row reduce to get ICI? Will the product be conserved?
  39. M

    Line of intersection of two planes

    Hi, I was doing a L.A question and a question arose. ( well I will write the question now, I found the answer I just can't visualize what I am doing which bothers me greatly) Find the equation of the plane that contains the line (x,y,z)=(1,0,0)+t(1,3,2), and is parallel to the line of...
  40. T

    Transfer *several* times as much data without increasing the size of the line

    Hey everyone, so for fiber optic networks we can either (in analogy) increase how fast the cars or photons move or add more lanes to increase the amount of data. What if now we use the color of the light to interpret several times more data?
  41. Baddum12

    Characteristic Spectrum and the K-alpha line

    I have just finished a junior-level lab assignment in which we used X-ray diffraction to determine the lattice constants of unknown materials. In the theory section of the lab write-up, it briefly explains the K-alpha doublet of the characteristic spectrum. I understand that it is the result...
  42. M

    Mapping 3D point to cone surface using perpendicular line

    Can someone please look at the diagram below and tell me how u1 is obtained. If it is through the use of m3 please explain how the gradient m3 is obtained.
  43. R

    Proving Gradient of Electric Field in Coaxial Line Dielectric is 0

    Homework Statement Show that (Grad dot E) =0 in the dielectric of a coaxial line. (Hint: apply the divergence theorem to a portion of the dielectric.) Homework Equations Divergence theorem The Attempt at a Solution I think I need to show that grad dot E = p/epsilon = 0 I don't know - I'm...
  44. D

    Identify emission line spectrum

    Homework Statement refer to the question Homework EquationsThe Attempt at a Solution from figure b , moving to the right, we know that the wavelength increases. since e= hc/λ , so the energy diffrenece should be increases as going to the right, so i consider line 1,2 and 3 is in a specific...
  45. I

    Line integral around a circle, using polar coordinates

    Given the force (derived from a potential in planar polar coordinates) F(p,w) = 2p+sin(w)e_p+cos(w)e_w Where e_p and e_w are unit vectors How do I calculate the line integral over a circumference that is defined as: p = 2 0 ≤ w ≤ 2pi Using the definition of a line integral \int_0^{2pi} \...
  46. L

    Line integral over vector field

    Homework Statement Let F be a vector field F = [-y3, x3+e-y,0] The path in space is x2 + y2 = 25, z = 2. My parametrization is r(t) = [5cos(t),5sin(t),2] Homework Equations Line integral is the integral of F(r(t)) * r'(t) dt, where here the asterisk * is for the dot product, not normal...
  47. steves1080

    How to size an orifice on a vent line

    I would like to install a vent stone on a 3/4" vent line. The line vents upwards of 1500 psig of stored gasous nitrogen in under 1 second. The vent stones are only rated for 300 psig, so I'd like to add an orifice just upstream to limit the exit flow rate to a point where it can handle the...
  48. I

    Line of action for which the resultant force of the wrench passes

    In tightening a bolt whose center is at point O, a person exerts a 180-N force on the ratchet handle with his right hand. In addition, with his left hand he exerts a 90-N force as shown in order to secure the socket onto the bolt head. Determine the equivalent force–couple system at O. Then find...
  49. S

    How do I know this point lies on the line in the plane?

    Homework Statement This is the point: (6,0,-2) Homework Equations x = 4-2t y = 3+5t z = 7+4tThe Attempt at a Solution Do I just plug in the points and see if I get matching values of t? If not, how do I go about this?
  50. H

    Why can a bird survive on a high voltage power line without getting fried?

    Homework Statement Birds can be seen perched on a high voltage power line yet seem unaffected by the high voltage. This is due to... A) Low resistance of the birds compared to the wire, minimizing current through the birds B) birds keeping only one foot on the wire, thus not completing a...
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