Cross product Definition and 465 Threads

  1. quasar987

    Cross Product in R^n: Defined or Undefined?

    Simple question: is the cross product defined in R^n ? In my linear algebra textbook, they talk about the dot product in length but don't even mention the cross product.
  2. M

    Cross product in non-cartesian coordinates?

    How do you go about crossing two vectors if they are in cylindrical coordinates? I have one vector in the direction of R and another in the direction of theta. Can this be done?
  3. tony873004

    The Mystery of the Minus Sign: Finding the Cross Product of a x b

    find the cross product a x b of the vectors a = 5.0m,i and b=4.3m,k 5.0m\ast 4.3m\ast \sin (90)=22m^2,\hat {j} The back of the book gives -(22m^2)\hat {j} Where does the minus sign come from?
  4. M

    Is the 2-Dimensional Cross Product Equivalent to a 90-Degree Rotation?

    I'm not even sure such a thing exists :P. Anyway, if it does, is it correct that it is: Xc = -Y Yc = X (rotation 90 deg counter clockwise) Couldn't find anything about it on google...
  5. M

    What are Cross Products and How Do They Relate to Tensors?

    I do not understand something about cross products. Say, \vec A\times \vec B=\vec C=(C_x, C_y, C_z) and, \vec C=(A_x \hat x+A_y \hat y+A_z \hat z)\times (B_x \hat x+B_y \hat y+B_z \hat z) but why is this equivalent to (A_x B_y - A_y B_x)\hat x \times \hat y + (A_x B_z - A_z...
  6. W

    Cross product in higher dimensions?

    Although, the dot product works in infitine dimensions, it is not the case for the cross product. Anybody know in what dimensions the cross product can be defined?
  7. Galileo

    Is there a simpler way to write the cross product of curl?

    Is there any neat way/rule to write: \vec B \times (\vec \nabla \times \vec A) ? I've tried it myself and found (e.g) for the x-component: \left(B_x\frac{\partial A_x}{\partial x}+B_y\frac{\partial A_y}{\partial x}+B_z\frac{\partial A_z}{\partial x}\right)-\left(B_x\frac{\partial...
  8. S

    How Does the Cross Product Help Calculate Tension in a Cable?

    In the problem: A horizontal boom supporting the sign is of uniform construction and weighs 50 N. If the sign weighs 150 N, the tension in the supporting cable is? Could I use the cross product and if so how? The answer is 350 N.
  9. G

    Using Cross Product to Find Torque

    Force F = (4.0 N) i + (-2.0 N) k acts on a pebble with position vector r = (2.50 m) j + (-1.3 m) k, relative to the origin What is the resulting torque acting on the pebble about a point with coordinates (2.0 m, 3.0 m, 2.0 m)? Ok so I just completely forgot how to work with vectors when...
  10. R

    Anyone have a clear definition of how to do a cross product?

    anyone have a clear definition of how to do a cross product?
  11. S

    How Can Two Perpendicular Vectors with Different Magnitudes Sum Up to (6, 8)?

    Find two vectors which are perpendicular, and one of them is twice the magnitude of the other. Also their sum should be (6,8). First of all let the coords be (x,y) and (a,b) then the magnitude of one of them is twice the other i .e . 2 \sqrt{x^2+y^2} = \sqrt{a^2+b^2} also their dot...
  12. 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...
  13. J

    Constant vector and cross product?

    Okay, here's the question: For r=xi + yj +zk evaluate grad x (k x r), where k is a constant vector. I know how to do the cross product of k x r and I know how to do grad x (k x r). But I don't know what k is. What's k?
  14. W

    Understanding the Cross Product of Vectors: Perpendicular Properties Explained

    Why does the cross product of two vectors produce a vector which is perpendicularto the plane in which the original two lie?(whenever i go to look it up it is already assumed that it is perpendicular)
  15. D

    What is the relationship between Dot and cross product vector?

    [SOLVED] dot and cross product vector Hi! The quantity (absolute value vectorA x vectorB close absolute value)^2 + (absolute value vectorA * vectorB close absolute value)^2 is equivalent to: I am confused, a close example used numbers in place of the vectors so I gave it a try in a book I...
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