Tetrahedron Definition and 77 Threads

  1. T

    How Do Orientations Affect Total Flow into a Tetrahedron?

    I'm working through Advanced Calculus: A Differential Forms Approach at my leisure. In going over two-forms the notions of "flow across an area" and "oriented area" are introduced I hit a brick wall with grasping orientations, though, when asked to find the total flow into a tetrahedron. So...
  2. M

    What is the volume of a tetrahedron formed by given points?

    Homework Statement Let points P1: (1, 3, -1), P2: (2, 1, 4), P3: (1, 3, 7), P4: (5, 0, 2)...form the vertices of a tetrahedron. Find the volume of the tetrahedron. Homework Equations V = 1/3 ah A = area of base h = height of tetrahedron The Attempt at a Solution I wanted to...
  3. MTd2

    Why spin foams just use tetrahedron and pentachoron?

    There is a big list of possible ways to tessellate space. But why just those 2 for 3 and 4 dimensions? http://en.wikipedia.org/wiki/List_of_regular_polytopes
  4. M

    Calculate Volume of Tetrahedron with Given Vertices | Step-by-Step Solution

    Homework Statement Find the volume of the tetrahedron with vertices at (0,0,0),(1,0,0),(0,1,0),(0,0,1) The Attempt at a Solution I worked out the triple integral and found out that the volume is \frac{1}{6} ? Is this correct? I know there is probably a much quicker way working the volume...
  5. P

    Calculating the Volume of a Tetrahedron using Integration Method

    Volume of Tetrahedron[Solved] My textbook opts to integrate with respect to y before x(dydx vs dxdy), so I assumed that it would not affect the outcome. I set the upper and lower bounds of y, respectively, as y = 24 - 7x/4 (from 7x+4y=96) to y = x/4 (from x = 4y). For x I set it from...
  6. D

    Tetrahedron car crash prevention

    Homework Statement Imagine a planet in the shape of a regular tetrahedron (its surface consists of 4 equilateral triangles). Suppose that on each face there is a car traveling at a constant speed in clockwise direction along the edges bounding the face. Can they travel without crashing...
  7. K

    Finding the Volume of a tetrahedron using Spherical Coordinates

    Find the volume of a tetrahedron under a plane with equation 3x + 2y + z = 6 and in the first octant. Use spherical coordinates only. The answer is six. x=psin(phi)cos(theta) y=psin(phi)sin(theta) z=pcos(phi) I've been trying to figure out the boundaries of this particular...
  8. P

    Proving the Sum of Vector Areas in a Tetrahedron is Zero

    Homework Statement Four vectors are erected perpendicular to the four faces of a general tetrahedron. Each vector is pointing outwards and has a length equal to the area of the face. Show that the sum of these four vectors is zero. Homework Equations The Attempt at a Solution Let A, B and C...
  9. D

    Calculating the Area of a Tetrahedron with Double Integral Calculus

    Consider the tetrahedron which is bounded on three sides by the coordinate planes and on the fourth by the plane x+(y/2)+(z/3)=1 Now the question asks to find the area of the tetrahedron which is neither vertical nor horizontal using integral calculus (a double integral)? I think they mean...
  10. K

    Electrix flux through a tetrahedron

    Homework Statement what is the outward flux through one of the 4 triangular faces of a tetrahedron centered at the origin if the charge density is q*(delta)^3(r) Homework Equations The Attempt at a Solution So, I figured that all I had to do was find the point charge q that the...
  11. E

    How can we easily find the volume of a tetrahedron with known side lengths?

    i strongly thought that if we know every side of the tetrahedron,we can confirm its volume. but i just puzzled about how to find out the expression. please help me!
  12. W

    Please, please, i need some hint about, tetrahedron

    Commandino’s Theorem states that The four medians of a tetrahedron concur in a point that divides each of them in the ratio 1:3, the longer segment being on the side of the vertex of the tetrahedron. can someone put links below where about proof of this theorem thx so much
  13. E

    Is Silicon-Oxygen Tetrahedron Bonding Ionic, Covalent, or Both?

    is silicon-oxygen tetrahedron(SiO4) stable or unstable? is there covalent or ionic bonding? Im not sure but i think it is stable and there's ionic boding. Silicon gives away one electron to every oxygen molecule making silicon a +4 ion and making each oxygen molecule have a charge of -1. b/c...
  14. B

    Volume of tetrahedron when you are given four planes

    Homework Statement I have to find volume of tetrahedron that is bounded between 4 planes. Planes are x+y+z-1=0 x-y-1=0 x-z-1=0 z-2=0Homework Equations \vec{a}=\vec{AB}=(X2-X1)\vec{i}+(y2-y1)\vec{j}+(z2-z1)\vec{k} \vec{b}=\vec{AC}=(X2-X1)\vec{i}+(y2-y1)\vec{j}+(z2-z1)\vec{k}...
  15. X

    Finding the inside angle of a tetrahedron

    Homework Statement "ASSIGNMENT 1 The Methane Molecule Introduction: The methane molecule CH4, composed of four hydrogen atoms and one carbon atom, is shaped liked a regular tetrahedron. The four hydrogen atoms are on the vertices and the carbon atom is at the center. What is the angle...
  16. A

    Volume of a tetrahedron using triple integration

    Homework Statement [FONT="Courier New"] Find the volume of the tetrahedron in the first octant bounded by the coordinate planes and the plane passing through (1,0,0), (0,2,0) and (0,0,3) Homework Equations [FONT="Courier New"]V=∫∫∫dV [FONT="Courier New"]...D The Attempt at a...
  17. DaveC426913

    Circumscribing a sphere with a tetrahedron

    I wish to drill four evenly-spaced holes in a ball. How do I form my construction lines so that my marks are accurate? Obviously, if I could circumscribe a tetrahedron inside (or outside) the ball its vertices (or face-centres) would mark my holes. But I can't do that. I need to scribe my...
  18. H

    Calculate some things about a tetrahedron

    Question Statement: Each surface of a tetrahedron ABCD is an equilateral triangle with each side 2 units long. The midpoint of AB and CD are L and M respectively. Calculate, by giving your answers correct to 3 s.f. or to the nearest 0.1 degree, a) The length of the perpendicular from A to...
  19. C

    Solve for H/L Ratio in Equal Tetrahedron

    Here's the problem: A regular tetrahedron is a three-dimensional object that has four faces, each of which is an equilateral triangle. Each of the edges of such an object has a length L. The height H of a regular tetrahedron is the perpendicular distance from one corner to the center of the...
  20. E

    What are the Lines of Symmetry in a Tetrahedron?

    Find the volume of "A tetrahedron with three mutually perpendicular faces and three mutually perpendicular edges with lengths 3 cm, 4 cm, and 5cm." This is how I visualized it: http://img282.imageshack.us/img282/9466/calculus31re.th.jpg The area of a triangle along the x-axis is: A(x) =...
  21. MathematicalPhysicist

    How Do You Find the Minimal Volume of a Tetrahedron Passing Through a Point?

    i have the point P(x0,y0,z0) i need to find the minimal volume of a tetrahedron which is constructed by a plane which crosses over point P, and by the axis planes. i got that the side of the tetrahedron is sqrt[(x-x0)^2+(y-y0)^2+(z-z0)^2], but I am not sure it's correct because then the...
  22. K

    Proving SA > (5)^(0.5) for ABCD Tetrahedron w/ Inscribed Sphere

    There is ABCD tetrahedron with inscribed sphere. S is a center of the sphere, radius of the sphere equates 1 and SA>=SB>=SC. Prove that SA>(5)^(0,5). I can't solve it. Could anybody help me?
  23. P

    Why NH3 is arranged as a tetrahedron

    why NH3 is arranged as a tetrahedron rather than arranged like the earth(N) is surrounded by 3 satellite(H)? O=C=O If is +ve, then it is repelled at its position but it will be attracted if it is at the position of . Why CO2 is still considered as a non-polar molecule? is exactly...
  24. Reshma

    Stokes' theorem over a tetrahedron

    Check the Stokes' theorem for the function \vec v = y\hat z Here it is over a tetrahedron. Stokes' theorem suggests: \int_s {(\nabla\times \vec v).d\vec a = \oint_p\vec v.d\vec r For the right hand side I computed the line integral from (a,0,0)--->(0,2a,0)--->(0,0,a)--->(a,0,0); which...
  25. G

    Calculus-Volume of tetrahedron and cross product

    Determine whether the points A = (1, 2, 3), B = (1, 1, 1), C = (1, 0, 2), and D = (2,-2, 0) are coplanar and find the volume of the tetrahedron with vertices ABCD. My professor did this problem in class as a review for an upcoming test and he didn't get the answer that was on the key. He...
  26. G

    Archived thread Volumes of Regular Icosahedron and Regular Tetrahedron

    Archived thread "Volumes of Regular Icosahedron and Regular Tetrahedron" Hi, The above-referenced thread is at this url address: https://www.physicsforums.com/archive/t-3876 I have something to add, having worked with this structure, in a bit of a different way, however, than is spoken...
  27. J

    Volumes of Regular Icosahedron and Regular Tetrahedron

    Please teach me. Is one Regular Icosahedron equal to twenty Regular Tetrahedrons ? If the edgelength of both Regular Polyhedras is 1, What would be their volumes ? Can we prove (or disprove) the equation below ? volume of Regular Icosahedron = 20 * volume of Regular Tetrahedron...
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