Prerequisite Knowledge

This tutorial assumes you know what either the dot product or the inner product and what orthonormal bases are. A good review can be found HERE. First we will look at the 3 dimensional case over the real numbers like in MA265 , and then we will extend our understanding to the n-dimensional case over F like in MA351 or MA353. We will also take a look at these problems from a computational standpoint, as is done in CS314, to give light to the purpose behind QR-factorization.

Gram-Schmidt

Projections

Let's say we have two vectors $ \vec{v_1} = \{ 3, 2, 0\}\quad and\quad\vec{v_2} = \{1, 2, 0\} $.


The Gram-Schmidt process is an algorithm by which we can orthogonalize a basis. The idea is the following.



Intuition

Let's say I've heard that the relationship between a person's height and their wingspan is approximately a 1:1 ratio. I'd like to test this theory and also come up with an equation that can estimate wingspan given a height. To get started, I've collected some sample data from a few of my friends.

Height (in.) Wingspan (in.)
67.75 67.25
64.25 64.50
75.75 73.50
62.25 61.75
62.75 60.75
66.75 66.25

The first thing I'm going to do is plot my data on a graph and sketch a line that I think is a good estimate for my data. It will look something like this.



Sources

http://jccc-mpg.wikidot.com/vector-projection

Alumni Liaison

Basic linear algebra uncovers and clarifies very important geometry and algebra.

Dr. Paul Garrett