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. YoungPhysicist

    Why am I getting an extra blank line at the end of my output?

    Note: this is not a homework question! The problem that this program should solve is turn a input like this:(no space and the end of the input string) james shawn charles nicholas into something like this: James Shawn Charles Nicholas But I keep getting an excess line at the bottom of all...
  2. opus

    Find eqn for "normal" line to the tangent- folium

    Homework Statement Back for more questions. This section has been pretty tricky. The graph of a folium with equation ##2x^3+2y^3-9xy=0## is given. Find the equation for the tangent line at the pont ##(2,1)## Find the equation of the normal line to the tangent line in the last question at the...
  3. opus

    Find eqn of Tangent Line to graph- Implicit Differentiation

    Homework Statement Find the equation of the tangent line to the graph of the given equation at the indicated point. ##xy^2+sin(πy)-2x^2=10## at point ##(2,-3)## Homework EquationsThe Attempt at a Solution Please see attached image so you can see my thought process. I think it would make more...
  4. B

    B How Can a Hydrogen Atom Emit Multiple Colors Simultaneously?

    If the spectral line of Hydrogen contains four colors, I don’t understand how the electron can jump four times to four different energy levels in the same moment?
  5. opus

    Find the slope of the tangent line to the function's inverse

    Homework Statement For ##y=f(x)##, find the slope of the tangent line to its inverse function ##f^{-1}## at the indicated point P. ##f(x) = -x^3-x+2## , ##P(-8,2)## Homework Equations The Inverse Function Theorem: ##(f^{-1})'(x) = \frac{1}{f'(f^{-1}(x))}## The Attempt at a Solution So...
  6. F

    Power line EMI filter + feedthrough filter for a Faraday cage

    Dear forumers, I need a 50hz 250VAC power line filter for an EMI shielding faraday cage. The filter should work between 100khz and 20ghz, attenuation should be >=60dB between 1mhz - 5ghz. Regular power line EMI filters like this don't seem to go that high (only up to a few hundreds of mhz...
  7. Marcin H

    Inductance of two-conductor line - Proof Questions

    I am trying to understand how to derive equations for the inductance of an x-conductor line. Any number really. But I want to understand the proof for a two-conductor line first. So to start any of these proofs you first need the equation for the per unit length inductance: I know R is...
  8. Navin

    Circle and a line dividing the circumference

    Homework Statement The line "4x + 3y -4=0 " divides the circumference of circle centred at (5,3) in ratio 1:2.whats the equation of the circle Homework Equations 2πr Distance of a line from point Radius of general circle The Attempt at a Solution I tried finding the distance of the centre...
  9. Marcin H

    Transmission Line Transposition - Conceptual Question

    This is more of a conceptual question and not a homework question. I am having a hard time understanding why we have to transpose transmission lines and how physically moving them changes anything. Do we only transpose in 3 phase transmission lines when we have 3 wires? Does the orientation...
  10. Faizan Samad

    Finding the equipotential surfaces of a finite line of charge

    Homework Statement Consider a line of charge stretching along the z-axis from -L to +L. Find the potential everywhere. What are the surfaces of constant potential. (The next question answers the previous question and says its a prolate ellipsoid. Homework Equations I will upload an image of...
  11. B

    MHB Find the equation of the line through (-9, 2); perpendicular to y= -1

    Find the equation of the line through (-9, 2); perpendicular to y= -1. Use standard form : y=mx+b
  12. gibberingmouther

    Line Integral for Electromagnetic Force

    http://web.mit.edu/sahughes/www/8.022/lec01.pdf So I'm trying to understand how to get from F = ∫[(Q*λ)*dL*r]/(r^2) to F=∫q*λ*[(xx+ay)/(a^2+x^2)^(3/2)]*dx Like I don't understand why the x and y components of r are negative, or why "The horizontal r component is obviously zero: for every...
  13. M

    How to compute distance of points to a line?

    I have computed a line from point A to point B by just subtracting the coordinates as below: line = np.array (x2-x1, y2-y1) I am not sure if I need to form the formula for this line first by computing the slope and intercept but I continued my code as below, slope being m and b being the...
  14. M

    I How to calculate angular rotation for a 2D line?

    For illustration purposes, I have attached an image of the line with the angle that I want to calculate. I am trying to determine the angle of rotation and the calculation that I am using currently is as below: angle = math.atan2(y,x) I use this formula to calculate the rotation for A and A'...
  15. N

    Find the center of a circle given a tangent line & point

    Homework Statement "Find the center and radius of the circle that passes through A(1,1) and is tangent to the line y=2x-3 at the point B(3,3). (Picture of the graph: https://imgur.com/a/0wAnqcU) Homework Equations Here's a link: https://imgur.com/a/y71Z9GY The Attempt at a Solution Soo, I've...
  16. M

    B How to calculate a perpendicular line?

    Hi, i get the math that is involved but if I have only the x,y coordinates for 2 points to connect and if i want to know what will be the perpendicular line to the line connecting these two points, how can I do that?
  17. L

    MHB Intersecon between a line and hypershere in R4 to RN

    Hello Again, If I have point B in an orthogonal n-space and point C at the origin of the same space, point_B = 0.03299720 0.00585822 -0.36979000 -0.43413200 -0.60787700 0.61335300 0.76003400 point_C = 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000...
  18. C

    Symmetric bowl associated with a line element

    Hi! I have the following problem I don't really know where to start from: A bowl with axial symmetry is built in flat Euclidean space ##R^3##, and has a radial profile giveb by ##z(r)##, where ##z## is the axis of symmetry and ##r## is the radial distance from the axis. What radial profile...
  19. S

    A Emission line core in sunspots

    What makes the core of some chromospheric lines such as the transition at 8542 A of the infrared Ca II triplet appear in emission in the dark umbra of sunspots?
  20. C

    Null geodesics given line element

    Hi, I'm the given the following line element: ds^2=\Big(1-\frac{2m}{r}\large)d\tau ^2+\Big(1-\frac{2m}{r}\large)^{-1}dr^2+r^2(d\theta ^2+\sin ^2 (\theta)d\phi ^2) And I'm asked to calculate the null geodesics. I know that in order to do that I have to solve the Euler-Lagrange equations. For...
  21. C

    I Christoffel symbols knowing Line Element (check my result)

    Hi! I'm asked to find all the non-zero Christoffel symbols given the following line element: ds^2=2x^2dx^2+y^4dy^2+2xy^2dxdy The result I have obtained is that the only non-zero component of the Christoffel symbols is: \Gamma^x_{xx}=\frac{1}{x} Is this correct? MY PROCEDURE HAS BEEN: the...
  22. Wrichik Basu

    MATLAB Troubleshooting Best Fit Line and Distance Calculation in MATLAB

    I have some experimental data, and I would like to plot a graph in MATLAB and also find the best fit line. I also want to find the distance between each point and the best fit line, and if the distance is greater than 1 unit, an error will be shown. For this, I have written a function. Here it...
  23. HastiM

    I 3p->2s: Why spectral line split into three lines in m. field

    Hello, suppose we have an excited hydrogen atom in 3p state which makes a transition to 2s state. Then the atom loses some energy by emitting a photon which can be detected (or seen). I have no problems with that situation. If there is an external magnetic field, the energy levels of the...
  24. L

    MHB Intersection between line and plane in R4-RN

    Hello, I believe that this is the correct forum for this post but please let me know if otherwise. I have the following data in R4, id x y z a B -0.0700177 0.382249 -0.289338 0.00349957 A 1.13388 1.77602 -0.679365...
  25. S

    A Number Line in Synthetic differential geometry

    Hello! I just start looking at SDG and I'm already having difficulties with a few concepts as expressed by A Kock as: "We denote the line, with its commutative ring structure (relative to some fixed choice of 0 and 1) by the letter R" "The geometric line can, as soon as one chooses two...
  26. E

    B The correlation between a dimensionless point and a line

    I see no correlation between a dimensionless point and a line although it appears that math has made one. I'm just a philosopher so it's quite possible that I've got it all wrong. It seems as though any location along a line is always the same location. If a location has no size then it can't...
  27. isukatphysics69

    Find the equation of a tangent line at each given point

    Homework Statement in title Homework Equations x=2cotθ y=2sin2θ dy/dx = 2sin3θcosθ y-y1=m(x-x1) point = (-2/√3,(3/2) The Attempt at a Solution Have been stuck for hours I solved for the dy/dx above, now I need to figure out how to get rid of the θ to get my equation in terms of x so I was...
  28. T

    Can a Copper Coil Harvest Power from Power Lines for an FM Radio Receiver?

    I had an idea of building an FM receiver that is powered from the electromagnetic fields generated by power-lines. My question is , how can I make the electromagnetic field receiving antenna? Will a simple copper coil work? If so, can the same coil be used as the RF antenna or will that have to...
  29. R

    Condition of tangency of a line on a general form parabola

    <Moderator's note: Moved from a technical forum and thus no template. Effort in post #3.> What is the condition of tangency of a line y=mx+c on parabola with vertex(h,k) ,say for parabola (y-k)2=4a(x-h)? I could only find the condition of tangency on standard form of parabola, in the internet...
  30. beefbrisket

    I Meaning of cross terms in line element

    In a problem from Hartle's Gravity, we are asked to express the line element in non-Cartesian coordinates u, v which are defined with respect to x, y. I have no problem getting the new expression for the line element, but then we are asked if the new coordinate curves intersect at right angles...
  31. A

    Lattice Diagram of a transmission line

    In lattice diagram, if the voltage wave is generated at Junction that there is an overhead transmission line before it, will the wave be in two directions with the same magnitude, or one in neglected ? Picture may illustrate .
  32. K

    Doppler shift of a hydrogen line on sun

    Homework Statement Homework Equations [/B] delta lambda/lambda = velocity/speed of light radius of the sun= 696 *10^6mThe Attempt at a Solution Hello, the solution states the correct answer for this problem is 5.8*10^-12m. This is exactly 2x my answer but i don't really know what i did...
  33. P

    Single Line Diagram - Power Systems

    Hey everybody, Its recurrent in Power System Analysis and Electrical Instalations the SL diagram. I need recommendations of books in which I can read about it. I've done a little research but couldn't find anything. Thats amusing, in which classes are this diagram teached for the first time...
  34. Poetria

    Region bounded by a line and a parabola (polar coordinates)

    Homework Statement ##r=\frac 1 {cos(\theta)+1}## y=-x A region bounded by this curve and parabola is to be found. 2. The attempt at a solution I have found the points of intersection but I am not sure what to do with the line (I need polar coordinates and it is not dependent on r :( )...
  35. O

    Find the distance from the point P to a line - linear algebra

    Homework Statement Find the distance from point P (1,7,3) to the line (x,y,z) = (-2,1,4) + s(1,-3,4), s is a free variable Homework Equations projnQP = ( QP⋅n/(lengthQP)(lengthn) )(n) The Attempt at a Solution I'm not quite sure about how to find the normal (n) here, but if I make s=0, I'm...
  36. J

    Method of images for a line source

    Homework Statement Consider the curve C (image attached). C coincides with the real-z axis for $$|z| > a$$ and, in $$|z| < a$$ C coincides with the semi-circle $$|z| = a, =z > 0$$ In terms of simple singular flows, what is the image in C of a line source of strength 2πm lying at z = z_0, above...
  37. R

    Coupling signals to a stripline transmission line

    Hello. I have a question about the place where signal enters or gets out from a line (strip or not) Sorry I don't know the exact word in english, may be tap or tapping ... For different lines 1/4 or 1/8 wavelength these points are sometimes @ a 1/4 from the cold point, sometimes elsewhere. I...
  38. Clara Chung

    Vector problem: distance between a point and a line

    Homework Statement Homework EquationsThe Attempt at a Solution My answer is d = |(a-b)x(p-b)|/|(b-a|). I first find out the area of the parallelogram produced by BA and BP and divide the area by length AB to get the height. Why am I wrong?
  39. W

    Problem with line integrals for electric potential

    Homework Statement I have a problem understanding the equation $$\Delta V = -\int_{a}^{b} \vec{E} \cdot d \vec{l}$$ In the case of a parallel plate capacitor whereby the positive plate is placed at ##z=t## while the negative is at ##z = 0##, my integral looks like $$\Delta V = -\int_{0}^{t}...
  40. S

    Electric Field of a Line of Charge

    If the electric field of a line charge at a distance 'a' is µ/2Π ε0a (µ is linear charge density), then the potential at that point should be µ/2Π ε0 (since potential = electric field x distance). This means that the potential is constant at every point around the line of charge. Hence, this...
  41. tomwilliam2

    Are two coincident lines the same line?

    Homework Statement My son's textbook says In a plane, given a line and a point not on it, at most one line parallel to the given line can be drawn through the point. He asked me why two lines couldn't be drawn on top of each other...to which I replied that they would have the same algebraic...
  42. Destroxia

    Calculating Christoffel Symbols from a given line element

    Homework Statement Given some 2D line element, ## ds^2 = -dt^2 +x^2 dx^2 ##, find the Christoffel Symbols, ## \Gamma_{\beta \gamma}^{\alpha} ##. Homework Equations ## \Gamma_{\beta \gamma}^{\alpha} = \frac {1}{2} g^{\delta \alpha} (\frac{\partial g_{\alpha \beta}}{\partial x^\gamma} +...
  43. billyray

    Estimate primary line coeffiecients

    Homework Statement Figure shows a 50 Hz, high-voltage, transmission line. The relationships between the sending and receiving end voltages and currents are given by the complex ABCD equations: where 'S' stands for sending-end and 'R' stands for receiving-end (a) Given the parameter...
  44. Marcus95

    Input impedance of a "Ladder" transmission line

    Homework Statement My electronics&physics lecture notes contain the following side note: ___ "A ladder transmission line comprises an alternating sequence of segments of two different transmission lines both of length $l$ with characteristic impedance $Z1$ and $Z2$. If the line is constructed...
  45. dRic2

    I Understanding the Eigenvalue Concept in Diffusion Equations

    I'm Sorry for the vague title, but I don't know what to write. Can someone tell me the meaning of the passage I underlined? Thank you Ric
  46. J

    Converter not starting up once line input voltage connect

    Hello guys, I have designed and built a prototype with the aid of PI Expert Designer tool according to the following characteristics: - Vinput = 85-305Vac - Voutput / Ioutput = 12Vdc / +700mAdc I also attach you the schematic of the converter, which was taken from DER-528 application note (14...
  47. billyray

    Transmission line coefficients

    Homework Statement A transmission line has the primary coefficients . R=2Ω/m L=8nH/m G=0.5mS/m C=0.23pF/m Determine the lines secondary coefficients Z0, α and β at a frequency of 1GHz Homework Equations included in upload The Attempt at a Solution included. I think its just a case of...
  48. A

    How to make thick line in 3D graphics (webGL)?

    Hi guys, I have a webGL application and my understanding is there is no option or at least the option to make thick lines is not working so I thought I would try to write my own routine. I suppose I could just make a double plot of the data just off-set a bit but I'm not exactly sure how to do...
  49. S

    Figure 3a shows a 50 Hz, high-voltage transmission line

    Homework Statement Figure shows a 50 Hz, high-voltage, transmission line. The relationships between the sending and receiving end voltages and currents are given by the complex ABCD equations: where 'S' stands for sending-end and 'R' stands for receiving-end (a) Given the parameter...
  50. K

    Calculating Line Integral in xy-Plane

    Homework Statement Calculate the line integral ° v ⋅ dr along the curve y = x3 in the xy-plane when -1 ≤ x ≤ 2 and v = xy i + x2 j. Note: Sorry the integral sign doesn't seem to work it just makes a weird dot, looks like a degree sign, ∫.2. The attempt at a solution I have to write something...
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