Vector projection (11/20/2008)

1. Main points

In today’s reading I learned that for equations that have any solution one can make approximate solutions. The main tool for doing this is using the dot product of vectors, obtained by multiplying corresponding coordinates of the vectors and adding. The most important fact about the dot product is that the dot product of two vectors is zero if the vectors are perpendicular and thus nonzero if the vectors are not perpendicular.

2. Challenging

Why is the dot product zero if the vectors are orthogonal?

3.Interesting

I found it interesting learning about methods to get approximate answers to equations and questions that do not have any solutions, I can see how this will can be very useful in statistics etc.