Hello I'm JowJow what a good situation is in this country, hope for the best. Learn, learn and keep learning.

I have learned vector in simple parts that was taught by Mr.Galuh.

›Scalar quantities

›Vector quantities

      Geometrically, the dot product of two vectors is the magnitude of one times the projection of the second onto the first. (scalar product)

*Scalar means no direction.

     

      Geometrically, the cross product of two vectors is the area of the parallelogram between them.(vector product)

*Vector means there is direction.

The right hand rule for cross multiplication relates the direction of the two vectors with the direction of their product. Since cross multiplication is not commutative, the order of operations is important.

1.Hold your right hand flat with your thumb perpendicular to your fingers. Do not bend your thumb at anytime.

2. Point your fingers in the direction of the first vector.

3. Orient your palm so that when you fold your fingers they point in the direction of the second vector.

4. Your thumb is now pointing in the direction of the cross product.

Dot product example(A=1i,5j,16k) (B=2i,6j,17k)

1i.5j.16k * 2i.6j.17k = 2i + 30j + 272 = 304

Cross product example (A=1i,2j,2k) (B=1i,2j,3k)

AxB = o , 2k , -3j = (2k-2k, -3j-2j, 6i-4i) = 0k, -5j, 2i

           -2k, 0, 6i

           -2j,-4i, 0

BxA = 0, 2k, -4j  = (2k-2k, -4i-6i, -4j-3j)

           -2k, 0, -4i

           -3j, -6i, 0

First, find the x, y
1st X, cos 30 * 20 = 1/2 √(3  * 20 = (?)
2n X cos 60 * 40 = 1 * 40 = 40