Points Definition and 1000 Threads

  1. andyrk

    Find Net Resistance b/w A & B in Attach 1: Explaining Equipotential Points

    Find the Net Resistance between A and B in attachment 1. The circuit in attachment 1 simplifies to attachment 2 from the fact that the points C and E are equipotential. Same goes for D and F. So we remove CE and F as no current passes through equipotential points. But why? How are these 2...
  2. A

    Simulating opposing rotational forces at different points on structure

    Hi, I am trying to simulate a tangential force acting on a point on a structure and the corresponding opposing force caused by the moment of inertia of a mass at a different position. In this image the structure rotates around point c and there is a vector out of mass m opposing the...
  3. D

    Calculating distance between origin and subsequent points

    Greetings helpful gentlemen and gentle women! The following is a problem I ran into during my internship. The background of my problem is biological/chemical in nature, so I’ll try to bother you as little as possible with the details. Thanks in advance for any help given. Homework...
  4. C

    How Does Zero Moment Point Influence Robot Stability?

    So I was reading up "Zero Moment Point -Thirty Five Years of Its Life" by Vukobratic for a presentation, and is said something like this: So if I am reading this right, it's saying the point where the GRF is acting upon will shift based on the magnitude of the force created by the...
  5. M

    Question about the collision of two objects (points) in space

    Hello. I am new to these forums. I don't really know if this is the right place to post this, but here it goes. I was thinking, what If there were two bodies (represented by points) in space (two dimensional space to keep it simple) with known position at time zero, where the first is moving...
  6. M

    Parameterising a line given by two points

    I'm working on a green's theorem integral and I'm given a line (0,0) to (1,2) which i parameterise as (t,2t) but the answer is actually (1-t, 2(1-t)) and if I use my parameterisation on the integral I get a different answer!
  7. D

    Find points where tangent line is horizontal

    Homework Statement Find the points on the graph of x3-y3=3xy-3 where the tangent line is horizontal Homework Equations y = f(x) so implicit differentiation must be used when taking the derivative of y (xy)' = xy' + y The Attempt at a Solution So if the tangent line is...
  8. L

    Qualitatively assessing melting/boiling points.

    Homework Statement Problem #1: List in order of increasing boiling points, n-pentane, neopentane, 1-chloropentane, and octane. Problem 2: List in order of increasing melting points, cyclohexane, n-hexane, trans-oct-3-ene, cis-oct-3-ene, acetanilide, and aniline. Homework Equations...
  9. B

    MHB Ask for constructing function from coordinate(x,y) points

    Hello, I'm new in this forum. I would like to know how to calculate to obtain the function expression of some given coordinate points(x,y). For example, if I have 6 coordinate points which are (x,y) (0.23, 4.5) (0.25, 6.5) (0.35, 8.8) (0.43, 15) (0.45, 17) (0.5, 25) The (x,y) relation...
  10. D

    Identifying Horizontal Tangents on the Graph of y = x^3e^x

    Homework Statement Find the points on the graph of y = x3ex where the tangent line is horizontal. (Your answer should include x-values and y-values) Homework Equations Product rule fg'+gf' The Attempt at a Solution (x3)(ex)+(ex)(3x2) x3ex+3x2ex= y' x3ex+3x2ex= 0...
  11. S

    Possible function y=f(x) if data points are given.

    How could one obtain a function y=f(x) that satisfies a number of data points (x_{i},y_{i}). That is how would it be possible to get a function if some points that are to lie on it have been given? I've seen some lectures on interpolation but all I've gotten is only the way to solve problems...
  12. I

    Metric on torus induced by identification of points on plane

    Hi all, Perhaps I'm asking the wrong question but I am wondering about the relationship between different definitions of, for the sake of argument, the torus. We can define it parametrically (or as a single constraint) and from there work out the induced metric as with any surface. But...
  13. D

    Find all the critical points of the function

    Homework Statement f(x) = x ln(x) The attempt at a solution f'(x) = product rule, resulting in 1 + ln (x) So by way of solving the problem, set 1 + ln (x) = 0 Now idealistically, find something in x that, when added to 1, equals zero. Now here's a problem I have. How do I know when to...
  14. O

    Average distance between random points in 2D

    I'm looking for an analytical solution to a very simple problem I've come across. Start with a circle of radius a. Now place n points at random positions inside this circle. Can you calculate the expectation value for the mean distance between the points? For the sake of argument can you...
  15. R

    Friction direction of a set of contact points

    Assume that a box is motionless and is located on the floor ground (one box's face touches the floor completely). If we apply a force to this box such that the box keeps its motionless state, what we can say about the friction directions of all contact points between the box and the floor? Are...
  16. Petrus

    MHB Tangent equation for two points.

    Hello MHB, I am doing some old exam and got less knowledge for this problem. consider the graph of the function g(x)=\frac{1}{x}, \ x\neq 0 the point \left(3,-1 \right) lies on two tangents to the graph. Decide tangents equation. My progress well I derivate and find the slope g'(x)=\ln(x) so...
  17. S

    Radial Distribution of Points over the Area of a Circle

    This is a tiny part of a presentation I am giving Friday, any and all help is appreciated. Homework Statement Suppose we have a circle centered on O. We are looking for the distribution of the points generated by the following method: We choose a random radius of the circle, and then choose...
  18. J

    Points relative to vectors. And Eq of line. Vectors

    Homework Statement Find the coordinates of α, β, and γ rel. to u, p, q (unit vectors) of x = 1/9( 2i + 62j - 11k )( (Note there orthogonal to each other) Question 2 : The position vectors of two points A, B has position vectors a = < 2, 1, 7> and b = <1, 4,-1> Find the parametric vector...
  19. Saitama

    Velocity of end points of rectangular frames

    Homework Statement (see attachment, ignore those marks done with the pen) Homework Equations The Attempt at a Solution I think this has to do with calculating torques and forces but I don't know about which point to calculate torque about. I know this is a very less attempt...
  20. F

    Does the path between two points always have to be contiguous?

    This is more of a hypothetical "it doesn't work, but WHY?", but what stops something from being at point A now, then moving to a different point an instant later without traveling through the space in-between? What makes it so that the motion we observe is always (nearly) contiguous? Is there...
  21. E

    How to determine all points of intersection in a polar coordinate

    Is there a way to find all points of intersection in a polar co ordinate graph without the need to draw the graph. i/e USing algebra? If so, how?
  22. D

    Points of intersection of Parametric Lines

    Homework Statement I'm told to find the 2 points the two curves P and Q will intersect on and the parametric equations are: P (x=t, y=2t-1) Q (x=3t-t^2, y=t+1) The Attempt at a Solution I know I'm supposed to set x-equations and y-equations equal to each and solve so that...
  23. S

    Average acceleration given velocity points?

    How do you find average acceleration given a table with points of velocity (ft/sec)? t (sec): 0 15 30 45 60 v(t) (ft/sec):0 40 60 70 75 the question asks: Find the average acceleration of Rocket A over t=[0,60] seconds. I used change in v(t)/change in time to find 4...
  24. R

    Melting Points as Function of P

    Hey folks, I'm trying to obtain the melting points of several materials in a vacuum. It's pretty straightforward to look up the melting point in 1 atm, but I'm having difficulty doing this in a vacuum. One material in particular I'm looking at is Teflon. If anyone can provide any...
  25. N

    Minimize distance between three points.

    Find the value of m such that the sum of the squares of the vertical distances from each of the points (1,1) , (2,2) , and (3,2) to the line y=mx is minimized. Hint: Find the sum as a function of m (no x in the expression) and then minimize it. Distance equation...
  26. AXidenT

    Finding Points on Curve where Derivative Doesn't Exist

    Homework Statement Find dy/dx on the curve 1/3*y^3 + y*sin(x) = 1 - x^6 At which points on the curve does this derivative does not exist? Find the slope of the line tangent to the curve at the point (0,3^(1/3)). Homework Equations dy/dx = - Fx/Fy The Attempt at a Solution I solved dy/dx...
  27. M

    Find an ellipse centered through the origin that runs through 3 points

    Find the ellipse centered at the origin that runs through the points (1,2), (2,2), and (3, I). Write your equation in the form $$ ax^2 + bxy + cy^2 = 1 $$ I understand the $$ ax^2 $$ and $$ cy^2 $$ in the equation because the equation of an ellipse centered at origin is $$ (x/a)^2 + (y/b)^2 = 1...
  28. R

    Parametric Analysis with ANSYS APDL: Joining Points and Counting KP Lines

    Hello everyone, I´m programming in ANSYS APDL and I want to make a parametric analysis. Because I need to join a lot of points with the bspline function I can´t make this FLST,3,10,3 FITEM,3,1 FITEM,3,-10 BSPLIN, ,P51X I need to write in my program all the points...
  29. C

    Fitting the 'tightest' rectangle to a set of three dimensional points

    I have a group of 8 3-D points which all sit on an arbitrary plane (The points were generated by projecting the corners of a axis aligned cube, box, onto the plane) I wish to group all the points in a rectangle with the smallest surface area - so a tight fit rectangle. What I am doing at...
  30. C

    Must On-Line Smooth Forecasted Point relative to previous points.

    This is a prediction that is made every day. If I do a back test assemble a curve composed of each days' prediction, I get fair results. However, if I smooth this backtest curve, I get fantastic results. So what I need to do is take today's prediction and the prediction time history...
  31. Saitama

    Vectors and points on a circle

    Homework Statement Let A, B, C, D be distinct points on a circle with centre O. If there exists non zero real numbers x and y such that ##|x\vec{OA}+y\vec{OB}|=|x\vec{OB}+y\vec{OC}|=|x\vec{OC}+y\vec{OD}|=|x \vec{OD}+y\vec{OA}|##, then which of the following is always true? A)ABCD is a trapezium...
  32. Feodalherren

    Points on ellipse where tangent slope=1

    Homework Statement 7 Find the points on the ellipse x^2 + 2y^2 = 1 where the tangent line has slope 1 Homework Equations The Attempt at a Solution I got the correct X and Y values but this gives me four possibilities and the answer key says there are two points. I got x...
  33. B

    MHB The equation of a hyperbolic paraboloid to derive the corner points of rectangle

    Hi Folks,I have come across some text where f(x,y)=c_1+c_2x+c_3y+c_4xy is used to define the corner pointsf_1=f(0,0)=c_1 f_2=f(a,0)=c_1+c_2a f_3=f(a,b)=c_1+c_2a+c_3b+c_4ab f_4=f(0,b)=c_1+c_3bHow are these equations determined? F_1 to F_4 starts at bottom left hand corner and rotates counter...
  34. M

    Do Manifolds have distance relations between points?

    Hello everyone, I am currently reading 'Geometrical Methods of Mathematical Physics' by Bernard Schutz and I have some questions about manifolds. I'm fairly new to Differential Geometry so bear with me! On P33 he states that 'manifolds need have no distance relation between points, we...
  35. F

    Find equilibrium points given 2 differential equation

    Homework Statement \dot{x} = -pxy + qx, \dot{y} = rxy - sy where p,q,r and s are positive constants (p does not equal r) Question is : Determine all the equilibrium points for the system of differential equations given above, expressing your answers in terms of p,q,r and s The...
  36. M

    Evenly distributed points on a sphere

    I have a practical application which relies upon the generation of evenly distributed points on a sphere. When I first considered this problem, I learned that some number of polyhedrons (Platonic polyhedrons) had each vertex lying evenly spaced from the others within the surface of a sphere...
  37. S

    Find all points where f(x) has a horiztonal tangent line

    1. Given. F(x) = 4x/(x^2+1) 2. Problem Find all points (x,y) where the function has a horiztonal tangent line 3. Attempt I took the derivative of F(x) and came to (-4x^2+4)/(x^2+1)^2 I set it equal to zero and found an x value of 1. I used that x value and plugged it into...
  38. C

    Identifying Points of Inflection: ABCDEFHJKL

    I'm supposed to identify the points of inflection in the following graph: I know the point of inflection is where concavity changes, and I keep getting stuck on one answer that is apparently not correct. I believe that the following points are points of inflection: ABCDEFHJKL A -...
  39. F

    China wants to raise the IQ of the next generation between 5-15 points

    I find it surprising that China has found a way to measure intelligence! Let's kill all diversity and raise a new generation that are good at taking IQ tests.
  40. C

    How Does Current Distribution Affect Magnetic Fields?

    Homework Statement A long metal cylinder of radius R is carrying a current ##I_C## into the page and the current in a second wire a distance 2R from the cylinder is set so that the magnetic field at point P is zero. Calculate: 1. the current in the second wire, 2. the magnetic field at the...
  41. L

    Interpolation of Infinitely Many Points

    This sort of came up the other day: Given a sequence of monotonically decreasing points, a_n, such that a_n \rightarrow 0 does there exist an analytic f on ℝ such that f(n) = a_n ? I figured there should be some sort interpolation theory on this, but I haven't found anything...
  42. A

    Magnitude of Potential Difference Between Two Points

    1. Homework Statement [/b] So I found this problem online, and I really do not know how to go about solving it! My professor has done similar problems in class, but it's still a little confusing. A current of 1.2 A flows from A to B. Therefore, the magnitude of the potential difference...
  43. B

    Finding distance between two origin points; waves

    1. A submerged scuba diver hears the sound of a boat horn directly above her on the surface of the lake. At the same time, a friend on dry land 22.0 m from the boat also hears the horn (Figure 1). The horn is 1.2 m above the surface of the water. What is the distance (labelled by"?" in Figure 1)...
  44. N

    Weird theorem on critical points for multivariable functions

    Why does it write all that stuff about fxy2? Isn't it unnecessary? I mean, isn't the following true? If in a point (a,b): fx=fy=0 and fxxfyy>0, then the partial derivatives must be either both negative or positive, and thus point (a,b) is a local minima or maxima. And if fxxfyy<0 => (a,b) is a...
  45. I

    MHB Fermat's theorem (stationary points) of higher dimensions

    Look at this page and the Proof part, Fermat's theorem (stationary points) - Wikipedia, the free encyclopedia How to change the proof 2 into a proof of higher dimensions or can you give a proof of Fermat's theorem of higher dimensions?
  46. P

    At what points on this curve is the tangent line horizontal?

    Homework Statement At what points on the curve y = (x^2)/(2x+5) is the tangent line horizontal? Homework Equations Quotient rule The Attempt at a Solution I figured out the derivative which is 2x(2x+5) - 2x^2 ----------------- (2x+5)^2 I also know that for the equation of...
  47. S

    Electric potential reference points confusion

    Hi gang, I am hoping you can clear something up for me. When evaluating the potential of a solid sphere, I find myself confused about the volumes used such that, \phi = Q \int_{\infty}^R \frac{1}{V_1} r^2 \sin(\theta) \, dr \, d\theta \, d\phi + Q \int_R^r \frac{1}{V_2} r^2 \sin(\theta) \...
  48. H

    Kinematic questions(velocity of 2 contact points)

    in the picture below http://tinypic.com/view.php?pic=9riq9l&s=6 if we know the angular velocity of the gear on the left, as well as their current distance from contact point, what can we say about the velocity of the right rod at the contact point at anytime t? we know it is not...
  49. S

    Cartesian 3D Vector Plotting Points?

    Homework Statement Plot the following point: B(-2,3,5) The Attempt at a Solution If I were to plot (-2,3,5), when I make my first movement of -2, it does not move anywhere on the y-axis correct and when I am moving on my Y axis, There is no movement in the z axis?
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