Line Definition and 1000 Threads

  1. M

    MHB Find Value of Squareroot of 3: Using the Graph & Quadratic Equation

    There is a graph in the form of $x^2-2x-3$ determine the value of $\sqrt{3}$ to the nearest decimal place by drawing an a suitable straight line What must be that straight line ? Usually these kind of problems are solved using the quadratic equation Many thanks :)
  2. yabb dabba do

    Transmisison Line Shunt Capacitance

    Why is there a shunt capacitance in a transmission line, but not in a normal circuit (non-transmission line).?
  3. yabb dabba do

    Current, B, E field directions on line in TEM mode

    Hi, Say you have a two conductor transmission line in TEM mode. The E and B field's will look something like the picture below with the E field in blue and the B field in red. The E field should point in the direction of the current, as it's what makes the charges move. The E field in the...
  4. S

    A Line integrals of differential forms

    Consider a curve ##C:{\bf{x}}={\bf{F}}(t)##, for ##a\leq t \leq b##, in ##\mathbb{R}^{3}## (with ##x## any coordinates). oriented so that ##\displaystyle{\frac{d}{dt}}## defines the positive orientation in ##U=\mathbb{R}^{1}##. If ##\alpha^{1}=a_{1}dx^{1}+a_{2}dx^{2}+a_{3}dx^{3}## is a...
  5. T

    MHB Finding Slope of Tangent Line: How-To Guide

    My professor shown us in class how to find the slope but I still don't understand
  6. joshua2112

    Transforming Cone Line Elements: Proving Flat Geometry?

    Homework Statement Consider the cone defined by z = √ x 2 + y 2 . By defining new coordinates ρ, φ where x = ρ cos φ, y = ρ sin φ, show that the line element on the cone is ds^2 = 2dρ^2 + ρ^2dφ^2 . Why does this result prove the cone has flat geometry? Homework Equations x=rcosφ y=rsinφ The...
  7. Clara Chung

    B Line absorption spectrum and stars

    Why can't hydrogen gas on the stars be detected by using line emission spectrum of hydrogen. Why must we use line absorption spectrum to detect?
  8. R

    Dynamics 1: Motion Along a Line

    << Mentor Note -- poster has been reminded to fill out the Attempt at the Solution part of the Template in future HH threads >>[/color] 1. Homework Statement An object of mass m is at rest at the top of a smooth slope of height h and length L. The coefficient of kinetic friction between the...
  9. C

    Slope of tangent line to curves cut from surface

    Homework Statement find the slope of tangent line to curves cut from surface z = (3x^2) +(4y^2) - 6 by planes thru the point (1,1,1) and parallel to xz planes and yz planes ... Homework EquationsThe Attempt at a Solution slope of tnagent that parallel to xz planes is dz/dy , while the slope of...
  10. Drakkith

    Slope of a Line Tangent to a Level Curve at a Point

    Homework Statement The equation ## f(x,y) = f(a,b) ## defines a level curve through a point ## (a,b) ## where ## \nabla f(a,b) \neq \vec 0##. Use implicit differentiation and the chain rule to show that the slope of the line tangent to this curve at the point ##(a,b)## is ##-f_x(a,b)/f_y(a,b)##...
  11. Kernul

    Build right triangle with two points and a line

    Homework Statement Given the points ##A (1, -1, 0)## and ##B (4, 0, 6)##, find the point ##P## of the line ##s## so that the triangle ##ABP## is a right triangle in ##B##. Calculate the area of the triangle. ##s : \begin{cases} x = 1 + 4t \\ y = 2 - 3t \\ z = 3 \end{cases}## ##\vec v_s = (4...
  12. Bishamonten

    Finding the point on the line of intersection between planes

    Homework Statement Given two planes, P1, P2. Find parametric equations for the line of intersection between the two planes. Homework Equations P1 = 2x -3y + 4z = 3 P2 = x + 4y - 2z = 7 The Attempt at a Solution Let N1 be the normal vector to P1, and N2 be the normal vector to P2. Then, N1...
  13. Marcus95

    Colinear points in a vectorplane

    Homework Statement If a, b and c are coplanar vectors related by λa+μb+νc=0, where the constants are non-zero, show that the condition for the points with position vectors αa, βb and γc to be collinear is: λ/α + μ/β + ν/γ = 0 Homework Equations Dot product Cross product Tripple product Vector...
  14. E

    250VDC Line, Transient detection

    Any of you guys know of any instrument to record both the DC and at the same time the AC transient of a DC line. Thanks.
  15. Kernul

    Line orthogonal to a plane with variable parameter

    Homework Statement I have to find for which values of the real parameter ##b## the following plane is orthogonal to the following line: ##\pi : 5x + (2b - 1)y - (1 + 8b)z + 3 = 0## ##s : \begin{cases} x + z - 4 = 0 \\ x - 3y + z + 2 \end{cases}## Homework EquationsThe Attempt at a Solution For...
  16. S

    Prove r(t) moves in a line, if a and v are parallel

    Homework Statement A point moves on a curve \vec { r } with constant acceleration \vec { A } , initial velocity \vec { { V }_{ 0 } } , and initial position { \vec { { P }_{ 0 } } } b. if \vec { A } and \vec { { V }_{ 0 } } are parallel, prove \vec { r } moves in a line c. Assuming \vec {...
  17. Kernul

    Line parallel to plane with real parameters

    Homework Statement Find for what real parameters the line ##r## is parallel to the plane ##\pi##. ##r: \begin{cases} x - 3y + 3 = 0 \\ 2y + z - 5 = 0 \end{cases}## ##\pi : 6x - (a - 1)y + 3az - 11 = 0## Homework EquationsThe Attempt at a Solution So, the only method I know is to put the three...
  18. moenste

    Find the wavelength of the blue line (line spectrum)

    Homework Statement The line spectrum of a certain substance consists of three prominent lines; blue (B), yellow (Y) and red (R). When the spectrum is examined with a diffraction grating having d = 4 * 10-6 m, it is found that the sequence of lines, moving from the centre, is B, Y, R, B, Y, B...
  19. newjerseyrunner

    B Combine a horizon line with expansion

    In this thread let's forget math, we don't have math to describe these energies anyway. Observation tells us that at extremely high energy densities there is some expansive force that vastly overwhelms everything else. Expansion has become the only viable explanation to what we observe. So I...
  20. H

    MHB Graph of function intersects line

    Explain why the graph of the function g (x) = x^3 - 2x + 1 intersects the line y = x in each of the intervals (-2, -1), (0, 1) and (1, 2). i hope someone can help me with this. To be honest i do not even know where to start. i sketched g(x) and y=x and i don't see them intersect in the...
  21. K

    What Is the Ideal Resistor Value for a Diode Circuit Using Load-Line Analysis?

    Homework Statement Determining the best resistance for my simple circuit consisting of a diode, battery, and resistor. Doing this using Load- Line Analysis Homework Equations ID = VD - V / R - Given by KVL[/B] (I can disregard n-pretend ) The Attempt at a Solution [/B] Here I have...
  22. Kernul

    Checking if line is orthogonal to two skew lines

    Homework Statement So, I'm doing a long exercise, you can check here the first part: https://www.physicsforums.com/threads/checking-if-the-following-lines-are-coplanar.885948/ The second part asks me to find, if one of the couple of lines are skew, the orthogonal line to two skew lines...
  23. superkraken

    Surface integrals and line integrals

    Homework Statement when we calculate the electric field due to a plane sheet or the magnetic field due to a wire,are we calculating it at a single point or the whole field due to the total wire? Homework EquationsThe Attempt at a Solution
  24. math4everyone

    What is the electric field at a point along the z-axis above a charged dome?

    Homework Statement Homework Equations The z component of the field: $$E_z = \frac{-Qh}{2\pi\varepsilon_0 (r^2+h^2)^{\frac{3}{2}}}$$ The Attempt at a Solution I tried to choose a cylinder for my Gaussian surface such that the radius of it matches with the distance d I am trying to find and...
  25. L

    I Points of a finite projective line

    I found in Thompson "From Error-Correcting to Sphere Packing and Simple Groups" this on page 131 How do you compute m/n in a finite field? Take the equivalence class 5 given above. Why does 2/5 and 18/22 give 5? thanks
  26. B

    Lossless transmission line characteristic phase constant

    Homework Statement A lossless transmission line has an inductance of 9.0 nH / m and a capacitance of 3.6 pF / m. a) What is the line's characteristic impedance? b) Calculate the phase constant of a frequency of 1 GHz. Homework Equations Equation of characteristic impedance of a transmission...
  27. Frankenstein19

    Help finding the angle between the force vector and line AO

    Homework Statement Find: The angle between the force vector and the line AO, and the magnitude of the projection of the force along the line AO Homework Equations cos(theta)=(A*B)/(|A|*|B|) The Attempt at a Solution I thought that since I'm given the force F in cartesian form, that I would...
  28. O

    I Solving Line Integral Limits: Negative Result?

    I want to the line integral in the following picture: The field is the blue arrows that go left to right, and the path is the orange line that is going from right to left. Just by looking at the picture, it is clear that the result will be negative, but when I set up the integration this is...
  29. C

    Comp Sci Fortran write statement working on 1 line & not the next

    Not really a question suited for the template...maybe shouldn't put this in Homework section, but it's for a class. My write files were being weird so I started some investigating. Below is an excerpt from the code. 58 OPEN(unit=33,file='random2.txt',status='unknown') 59...
  30. S

    Velocity of charge orbiting infinite line of negative charg

    Sorry I couldn't finish the title. I ran out of space. Anyway, here's the question: A uniformly charged, infinitely long line of negative charge has a linear charge density of -λ and is located on the z axis. A small positively charged particle that has a mass m and a charge q is in circular...
  31. S

    Find the equation of the plane parallel to two lines

    Homework Statement Let A, B and C be distinct vectors in V3 with B and C non-parallel. a. Find an equation for the plane containing both the line through A parallel to B and the line through A parallel to C. b. Verify that the two lines actually lie in the plane. Homework EquationsThe Attempt...
  32. blue_leaf77

    Is Line able to associate e-mail accounts with phone numbers?

    So here is the situation, I just got to know a certain person and I was recently notified through my Line that he added me as his friend. I have his phone number but he doesn't have mine. All he has about my contact is my e-mail. However, when making a Line account I was not asked to input my...
  33. J

    MHB Locus of Line Segment Mid Point Intercept Real/Imaginary Axis

    Find locus of mid point of line segment intercept between real and imaginary axis by the line $a\bar{z}+\bar{a}z+b=0,$ where $b$ is areal parameter and $a$ is a fixed complex number such that $\Re(a),\Im(a)\neq 0$ My Attempt:: Let $z=x+iy$ and $a=x_{0}+iy_{0}$, Then put into...
  34. L

    Transmission line impedance question

    I am a bit confused on source impedance and Tline impedance, when both are equal. Let's say source impedance is 50 ohms and Tline imepdance is also 50 ohms. Why does the incident wave divide between the source impedance and tline impedance. The impedance is same, so reflection co-efficient...
  35. Einstein's Cat

    B Line Equations: Rearranging Ax + By + C = 0 to y=mx+b

    Say a line equation is expressed with the General equation of Ax + By + C = 0; can one just simply rearrage this into the form of y= mx + b?
  36. T

    Transmission line and measuring Zo

    Homework Statement Figure 2: Homework EquationsThe Attempt at a Solution 3.2) I made an equation for the input voltage and input current Vi = Vs*(Zi)/(Zi+Rs+Rm) Ii = Vs/(Zi+Rs+Rm) I am a bit confused about what voltages V1 and V2 are measuring, and what do they mean by using the phase ...
  37. J

    MHB Slope of Tangent line to Polar curve

    I am trying to find the slope of the tangent line of this polar equation: r = 4 + sin theta, (4,0) I put the equation into wolfram alpha and it gives me a 3D plot. If someone could help me find the slope of the tangent line, I would really appreciate it. Thank you.
  38. S

    Tangent line and normal on a parabola

    Homework Statement If the normal at P(ap^2 ,2ap) to the parabola y^2 = 4ax meets the curve again at Q(aq^2, 2aq), show that p^2 +pq+2=0 Homework Equations Point-slope form The Attempt at a Solution I tried putting y=2aq and x=aq^2 but I can seem to simplify the whole thing other than...
  39. A

    How can I draw a line in assembly language without using decimal numbers?

    i have a frame-buffer , and i want to draw a line using assembly language . i cannot work with decimal numbers . what's the best and most efficient method ? thank you .
  40. S

    Line integral across a field given by circular distribution

    Homework Statement Evaluate \int_C \vec{F} \cdot d\vec{r} Where \vec{F} is the field generated from a circular thread of radius b in the xy plane, with magnitude j in the direction \hat{\varphi} (i.e. not along the curve, I take it) C: (x,y,z) = b(1+ \cos{\alpha}, 0, \sin{\alpha}) 3. The...
  41. B

    MHB Coordinates of Point H in GH Line

    GH is a straight line. the coordinates of G are (-2,8) the midpoint of GH is (5,-3) work out the coordinates of H
  42. pluviosilla

    I Slope of LS line = Cov(X,Y)/Var(X). Intuitive explanation?

    The slope of a fitted line = Cov(X,Y)/Var(X). I've seen the derivation of this, and it is pretty straightforward, but I am still having trouble getting an intuitive grasp. The formula is extremely suggestive and it is bothering me that I can't quite see its significance. Perhaps, my mental...
  43. S

    I Is a function better approximated by a line in some regions?

    I studied Taylor series but I would like to have an answer to a doubt that I have. Suppose I have ##f(x)=e^{-x}##. Sometimes I've heard things like: "the exponential curve can be locally approximated by a line, furthermore in this particular region it is not very sharp so the approximation is...
  44. E

    Fortran What does this Fortran Line Mean?

    This is the line: read(A, *) B The variable A is defined earlier in the code. I searched around the internet, and the 'read' syntax requires an input from the keyboard. However, the syntax I saw is read(*, *) var, so the two arguments are both asterisks. What if the first asterisk is defined...
  45. C

    Line integral of scalar field ( piecewise curve)

    Homework Statement for the line segment c2 , why did the author want to differentiate dx with respect to dy ? and he gt dx = 0 ? I'm curious why did he didnt do so for C3 , where dy= 0 ..Why didnt he also differentiate dy with dx ? dy/dx = 0 ? Homework EquationsThe Attempt at a Solution is...
  46. M

    Reclaimed Oil Line Same Return Rate

    I am re-piping a oil line use for burning reclaimed oil and currently the oil returns to the tanks to the bottom of the tanks. I want to have them return to the top of the tanks to increase the mixing of the oil. My only problem is that their are two tanks that will fill up by the same oil line...
  47. physicality

    I Conformal transformation of the line element

    Let us see how the line element transforms under conformal transformations. Consider the Minkovski metric gij, a line element ds2=dxigijdxj, and a conformal transformation δk(x)=ak + λ xk + Λklxl + x2sk - 2xkx⋅s We have δ(dxk)=dδ(x)k=λ dxk + Λkldxl + 2 x⋅dx sk - 2dxkx⋅s - 2xkdx⋅s And so the...
  48. K

    I Green's theorem and Line Integrals

    (Sorry for my bad English.) I was reading about the Green's theorem and I notice that the book only shows for the case where the function is a vector function. When learning about line integrals, I saw that we can do line integrals using "ordinary" functions. For example, the line integral of...
  49. P

    I How can larger dips in absorption line give more element

    So I just learned that in a spectrum like this one: (For now, let's concentrate on the graph given below.) The longer the dip is in the graph, the more the corresponding element is present. However, if each individual color corresponds to a different element, then how can a larger dip mean...
  50. M

    B Is the intersection of two planes a line?

    This is not a homework question. School year has ended for me and I'm doing some revision on my own. I want to proof the following because in an exercise I had to find the equation of the line that passed through a given point and 2 given lines. If a line r intersects with 2 given crossing...
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