Hello, vinh48!

I know HOW to use a scalar product.

However I don't know why do we need it and need a image of the result.

As far as I know, the scalar product has no immediate meaning or image,

. . but it is used in a variety of formulas.

Given two vectors: .

. .

. .

. .

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

I suggest that the scalar product is "similar" to a determinant.

A determinant has a value which, by itself, is meaningless.

However, it can be used in a variety of ways (e.g. Cramer's rule)

. . for a number of mathematical tasks.