Believe the matrix.

To show people that I have been doing some work at home, and since I dun really have anything else to blog about these days except my new R4 and level 100 lapras, I'll do some math.

The topic today is on Matrices, which I felt was severly glossed over by the SRJC math department. (Read:They suck)

As a recap, I'll use the example;

2x + 6y = 5
3x + 3y = 10

To put that into matrix form, it becomes

(2 6 5 )
(3 3 10)

Subtracting two times of row 2 from three times of row 1, or 3R1-2R2->

(0 12 -5)
(3 3 10)

Switiching,

(3 3 10)
(0 12 -5)

This gives,

y = -5/12 and
3x + 3y = 10
x = 1/3[10-3(-5/12)]= whatever this is.

Of course there is another method using inverse matrices,

(2 6)(x) = (5 )
(3 3)(y) = (10)

First we find the inverse of (2 6),(3 3)

Which is 1/24 of the matrix (-6 12),(6 -4)

Multiplying that to the equation at the top gives
(1 0)(x) = 1/ (-6 12)(5 )
(0 1)(y) = 24 (6 -4)(10)

of course (1 0),(0 1) is just the identity matrix which acts like 1, so,

(x) = 1/ (-6 12)(5 )
(y) = 24 (6 -4)(10)

And we have the same answer as before. Or we should.
Of course all this is just simple secondary school stuff, more on matrices next time LOL.
In particular, I'll do inverse matrices and the rotation matrix, which again is elementary stuff but largely left out unwisely by the A level syllabus.