Friday, April 15, 2011

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.

Monday, April 4, 2011

Dissidia is cool.

My god its been one month since i blogged. Not my fault, nothing much to write about these days. Everyone is in the army or working.

Me? I've been playing video games. There seems to always be an endless supply of video games to play. I can never ever finish them all. Just like homework. Just to give you list, theres-

Dissidia 012
Parasite Eve: The Third Birthday
Golden Sun
999
All the Kingdom Hearts games, of which there are at least 3.
Metroid Prime
Mario Galaxy
Grand Theft Auto IV ........

The first two of which are AAA titles for the PSP. I'll bet there're more, I just can't remember.

Oh I've been studying partial differentiation too. Really hard to visualize everything in 3D.

And nope, I'm not gonna find work.