# Game Creation with XNA/Mathematics Physics/Vectors and Matrices

## Vectors and Matrices

editWe need to recall some basic facts about vector and matrix algebra, especially when trying to develop 3D games. A nice introduction with XNA examples can be found in the book by Cawood and McGee. ^{[1]}

### Right Triangle

editOnce upon a time there was little Hypotenuse. He had two cousins: the Opposite and his sister the Adjacent. Both were usually just known by their nick names 'Sine'^{[2]} and 'Cosine'^{[3]}. They lived together in a *right triangle* close to the woods. They were related through his mother's sister, aunty Alpha. His father, who was a mathematician, used to say that:

Sometimes he also referred to uncle Tangent (who was married to aunty Alpha) and said that

so in a sense uncle Tangent of aunty Alpha was Sine divided by Cosine. To us that didn't make any sense, but Hypotenuse's father said that was how it always was.

### Vectors

edit### Matrices

edit### References

edit- ↑ S. Cawood and P. McGee (2009).
*Microsoft XNA Game Studio Creator’s Guide*. McGraw-Hill. - ↑ Wikipedia:Sine
- ↑ Wikipedia:Cosine