192 replies to this topic

[MdaG]

Beeeeeeeeeeeeeeeeeef! Your're a maths major right? I suck at proofs and such, I'm prefer applied maths. Could you take a peak at 1.2 ? Link

If this is a continuous state

px(t) = Ax(t) + Bu(t) (p = differential operator with respect to time)

then this is a sampled state of the continuous state

x[kh +h] = Fx[kh] + Gu[kh] (h = sampling period, kh <= t < (k+1)h)

A, B, F and G are matrices.


I don't know where to begin.

[DannyMc252]

I learn maths well. I just dont like my teacher. For 2 years running.
She still thinks Im a genius.

[BeefontheBone]

Sorry, that's not my area I'm afraid - I'm more of a logician/algebraist, with a little bit of applied and discrete thrown in - not too hot on the old statistics.

[DannyMc252]

I was just doing maths homework, and stumped by something about 4 sides, 70 degrees, an isosceles triangle and alot more angles.
10 minutes passed...




Then I noticed the word 'rectangle' underneath the shape.

[Doubler]

Yay, I propably botched up my maths exam last week
Ugh, and this was the easy part. Next period we'll have to proof things, and do all kinds of other weird stuff. The few things I managed to do last year now long forgotten

Why ω why did I choose the highest level of maths available on Dutch high schools?
I don't even like maths...
*wanders off muttering to himself*

[DeathDude]

I know what ya mean Doubler, I took the highest math in High School too, mostly because all the places here want those courses on your transcripts, sigh worst 3 years of math of my life, I shall never again do math in school again, save simple math of course.

[MdaG]

BeefontheBone, on Nov 9 2005, 12:25 AM, said:

Sorry, that's not my area I'm afraid - I'm more of a logician/algebraist, with a little bit of applied and discrete thrown in - not too hot on the old statistics.

Bummer, I think I have a plan on how to solve it now. Thanks  

*edit*
Made some progress, but I need some kind of "enlightenment" to finish it off now.  

*edit*
I think I have something that'll have to suffice as a proof now.

*edit*
Solved it !  

[DannyMc252]

I have tests in May.
And I got told today that I'm hacing a mock tomorrow.
I managed to escape the intolerable nocks for 3 years.. BUT THEY HAVE FOUND ME! OH GOD WHY!

[Sean]

Probably because you cant type properly!

On Topic:

(Ax+3)(x+a)

Equals?

(I had to throw something on topic in there... thats a random sum.. have fun with it!)

[MdaG]

Magic, on Nov 10 2005, 08:41 PM, said:

Probably because you cant type properly!

On Topic:

(Ax+3)(x+a)

Equals?

(I had to throw something on topic in there... thats a random sum.. have fun with it!)

What do you mean by it being a random sum?

The only thing I can get out of it is that it's equal to: Ax^2 + (Aa + 3)x + 3a.

[DannyMc252]

Magic, on Nov 10 2005, 06:41 PM, said:

Probably because you cant type properly!

On Topic:

(ax+3)(x+a)

Equals?

(I had to throw something on topic in there... thats a random sum.. have fun with it!)

a2x+2ax+3x+3a

assuming A and a are the same.

[BeefontheBone]

If they're the same, your first term should be (ax)^2.

[Havell]

BeefontheBone, on Nov 10 2005, 07:32 PM, said:

If they're the same, your first term should be (ax)^2.

Nope, I should be ax^2+xa^2+3x+3a (as there isn't another "ax" on on other side to multiply it with).

[BeefontheBone]

Doh, wrong brackets - it's a(x^2), of course.

[MdaG]

My answer is better!  

I'm also quite fascinated at how certain sums converges or diverges.

For example the sum: 1 + 1/2 + 1/ 3 + 1/4 + ... will become infinite

while: 1 + 1/4 + 1/9 + 1/16 + 1/25 + 1/ 36 + ... will converge

another thing I like is how you can approximate a function with for example Taylor or Fourier series. That's cool !!!