Prove (u+v) x (u-v) = 2v x u (Cross product)

In summary, the cross product is a multiplication operation between two vectors that results in a third vector perpendicular to the original two. It is calculated using a formula involving the magnitudes of the vectors, the angle between them, and a unit vector. The cross product is only defined for three-dimensional vectors and has applications in physics, engineering, and computer graphics. It satisfies the properties of linearity and distributivity, making it a useful tool in vector algebra.
  • #1
ohiggins
1
0

Homework Statement



Show that (u+v) x (u-v) = 2v x u

Homework Equations



being u=(x1,y1,z1)
and v= u=(x2,y2,z2)

The Attempt at a Solution



I've got 2v x u equals:

(2y2.z1 - 2z2.y1) + (2x2.z1 - 2z2.x1) +
(2x2.y1 - 2y2.x1)

But I'm nearly to melt my mind to prove (u+v) x (u-v) = above
 
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  • #2
Expand the product, and use that property of the cross product that uxv=-vxu and the product of identical vectors is zero.

ehild
 

Related to Prove (u+v) x (u-v) = 2v x u (Cross product)

What is the definition of a cross product?

The cross product, also known as the vector product, is a type of multiplication operation between two vectors that results in a third vector that is perpendicular to the original two vectors. It is denoted by the symbol "x" and is only defined for three-dimensional vectors.

How is the cross product calculated?

To calculate the cross product of two vectors, u and v, we use the following formula: (u x v) = (|u| * |v| * sinθ) * n, where |u| and |v| are the magnitudes of the two vectors, θ is the angle between them, and n is the unit vector perpendicular to both u and v in the direction determined by the right-hand rule.

Can the cross product be used for any type of vector?

No, the cross product is only defined for three-dimensional vectors. It cannot be used for two-dimensional or higher-dimensional vectors.

What is the significance of the cross product in physics and engineering?

The cross product has various applications in physics and engineering, such as calculating torque, magnetic force, and angular momentum. It is also used in 3D graphics and computer vision for operations such as calculating surface normals and determining the orientation of objects.

How does the cross product satisfy the properties of linearity and distributivity?

The cross product satisfies the property of linearity because it follows the rule (au + bv) x c = a(u x c) + b(v x c), where a and b are scalars and u, v, and c are vectors. It also satisfies the property of distributivity due to the rule (u + v) x c = (u x c) + (v x c), where u, v, and c are vectors. These properties make the cross product a useful tool in vector algebra and allow for simplification of complex equations.

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