four points Definition and 11 Threads

  1. M

    Number of lines equidistant from four points on a plane

    Hi, i'm trying to solve this problem. It's exercise 3 on page 5 from this book: Challenging mathematical problem with elementary solutions The solution is on page 41: I'm OK with the 4 circles in case 1: i can pick (inside/outside): ABC + D, ABD + C, ADC + B, BCD + A. What i cannot...
  2. R

    MHB Equation of a plane determined by three or four points in R4

    How do you find the equation of a plane in determined by say three or four points in $\mathbb{R}^4$? In $\mathbb{R}^{3}$ we would use the cross product to find normal vector, but that doesn't apply in $\mathbb{R}^4$.
  3. T

    Show that four points lie on a plane

    Homework Statement (2; 0; 1); (-1; 2; 3); (3; 2; 2) and (3;-6;-3) Homework Equations PS→⋅(PR→×PQ→)=0 The Attempt at a Solution Hi all, I am just wondering if my calculations are correct, and in fact these points do not lie on a plane. My answer is = 50 and i am not confident. Can...
  4. D

    Find Cubic Equation from Four Points?

    I am working on finding the area of a solid object. I have 4 points that I need to calculate a cubic equation from. I have tried relentlessly but to no avail I always get the wrong answer. The four points are;(0,2.7) (0.5, 2.9) (1,3.2) (1.9, 3.4) Using excel, the formula should be...
  5. Nero26

    Test for coplanarity of four points

    Hi all, If a,b,c,d are position vectors of four points A,B,C,D.The points will be coplanar if xa+yb+zc+td=0,x+y+z+t=0,provided x,y,z,t are not all 0,and they are scalars.Is this test needed to show 4 points are coplanar? If we consider two lines joining A,B and C,D then this will give us two...
  6. P

    Plate four points bending equation for a plate

    Hello, I am no mechanical engineer and my knowledge in bending is limited to Euler-Bernouilli beam theory. I wish to analytically calculate the normal stress of a plate bent by four points bending. I have already calculated this stress for a beam. However I cannot apply the beam theory...
  7. N

    Vector proof - four points in space

    The problem is: A, B, C, D are any four points in space. If M and N are the mid-points of AC and BD, show that AB + CB + CD = 4MN. I'm not quite sure where to start. Could someone please help me?
  8. 5

    Find the four points at which two lines are tangent to both parabolas

    Homework Statement Draw a diagram to show that there are two lines tangent to both of the parabolas y = - x^{2} (1) and y = 4 + x^{2} (2) Find the coordinates of the four points at which these tangents touch the parabolas. Homework Equations y - y_{o} = m(x - x_{o}) The Attempt at a...
  9. J

    Determining Coplanarity of four points

    How do you determine Coplanarity of four points? I am given A(3,1,0), B(2,-3,1), C(-1,0,4), D(5,-6,-2). Do i make vectors for each point from the origin? (But that wouldn't work would it? :() Can anybody point me in the right direction? Thanks!
  10. V

    (Multivariable Calc) Given four points, find a sphere.help me.

    Homework Statement Find the radius and center for the sphere determined by the four points (3,2,-1), (5,-2,1), (-3,1,2), (0,2,4). Give the exact location of the center but approximate the radius to the nearest 0.1.Homework Equations Equation of a sphere: x2 + y2 + z2 + Gx +Hy +Iz +J = 0 or...
  11. S

    Finding Ratios Using Mass Points in Triangles with Four Points

    Homework Statement Find the ratio EH:HG. Please, see the full question with a picture here: https://dl.getdropbox.com/u/175588/problem.JPG Homework Equations "In triangle ABC, let D and E be the trisection points of BC with D between B and E." Please, see the full question with a picture...
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