Derivative of outer product of vector to time D / dt (a × b) is the derivative of the outer product of vectors a and B to time

Derivative of outer product of vector to time D / dt (a × b) is the derivative of the outer product of vectors a and B to time

Take the third-order vector as an example, first, let a = (A1, A2, A3), B = (B1, B2, B3), find (a × b) = (a2b3-a3b2, a3b1-a1b3, a1b2-a2b1), and then derive it. The derivation method is to derive the three coordinates of the vector

Given a + B = (2,2), A-B = (- 4,6), find the coordinates of vectors a and B

a+b=(2,2)
a-b=(-4,6)
2A = (- 2,8)
a=(-1,4)
b=(2,2)-a=(2,2)-(-1,4)=(3,-2)

Given the coordinates of the vector, how to find the size of the vector?
For example: vector a = (root 3, - 1), find the size of vector a

If the coordinates of the vector are (x, y), then the vector size is √ (X & sup2; + Y & sup2;)
So | a | = √ (3 + 1) = 2

[given the coordinates of two vectors, how to find the coordinates of the intersection point of vectors?]

This is not right
The vector we learn, whether it is a plane vector or a space vector, is a free vector;
If the intersection problem is not involved, there is no point submitted, let alone coordinate calculation;