The following representation: (a+beta′ X)^2 where a is a constant and both beta and X are k by 1 vectors.

Hagman7v

Hagman7v

Answered question

2022-09-14

I have the following representation:
( a + β X ) 2
where a is a constant and both β and X are k by 1 vectors.
The representation is further written as follows:
a 2 + 2 a β X + X β β X )
While the first part is clear to me, I struggle to understand why it is shown once with ′ (X′ and β ) and once without ′ (X and β).

Answer & Explanation

cercimw

cercimw

Beginner2022-09-15Added 8 answers

here denotes the transpose vector. Since both β and X are k × 1 vectors, β X is a scalar, so β X = ( β X ) = X β, and
( β X ) 2 = ( β X ) ( β X ) = X β β X .

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?