-
this is what hell really looks like
2003-02-22 19:03:42
The following is a log of a Maple session I had when solving a practice problem for my Calculus final exams. I don't need to give context, because, well, the only really neat thing for you guys to look at is the sheer messiness of it all. If you know the mathematics, it's even better.
restart;
> v1:=m*diff(v(t), t)=-32*m + k*v(t)^2;
/d 2
v1 := m |-- v(t)| = -32 m + k v(t)
dt /
> subs(v=219, rhs(v1));
2
-32 m + k 219(t)
> solve(0=%, k);
32 m
-----
47961
> k:=%;v1;% / m;simplify(%);v1:=%;
32 m
k := -----
47961
/d 32 2
m |-- v(t)| = -32 m + ----- m v(t)
dt / 47961
32 2
-32 m + ----- m v(t)
d 47961
-- v(t) = ---------------------
dt m
d 32 2
-- v(t) = -32 + ----- v(t)
dt 47961
d 32 2
v1 := -- v(t) = -32 + ----- v(t)
dt 47961
> diff(v(t), t) / rhs(v1);
d
-- v(t)
dt
-----------------
32 2
-32 + ----- v(t)
47961
> int(%, t);
219 219
--- ln(v(t) - 219) - --- ln(v(t) + 219)
64 64
> % = t + C;
219 219
--- ln(v(t) - 219) - --- ln(v(t) + 219) = t + C
64 64
> velo:=solve(%, v(t));
/ 64 t 64 C
219 |1 + exp(---- + ----)|
219 219 /
velo := - --------------------------
64 t 64 C
exp(---- + ----) - 1
219 219
> solve(0=subs(t=0, velo), C);
219
--- I Pi
64
> C:=%;
219
C := --- I Pi
64
> velo;
/ 64 t
219 |1 + exp(---- + Pi I)|
219 /
- --------------------------
64 t
exp(---- + Pi I) - 1
219
> simplify(%);
/ 64 t
219 |-1 + exp(----)|
219 /
- --------------------
64 t
exp(----) + 1
219
> velo:=%;
/ 64 t
219 |-1 + exp(----)|
219 /
velo := - --------------------
64 t
exp(----) + 1
219
> unassign('C'); pos:=int(velo, t) + C;
47961 64 t 47961 64 t
pos := ----- ln(exp(----)) - ----- ln(exp(----) + 1) + C
64 219 32 219
> solve(11400=subs(t=0, %), C);
47961
11400 + ----- ln(exp(0) + 1)
32
> C:=%;
47961
C := 11400 + ----- ln(2)
32
> pos;
47961 64 t 47961 64 t 47961
----- ln(exp(----)) - ----- ln(exp(----) + 1) + 11400 + ----- ln(2)
64 219 32 219 32
>
> solve(1800=pos, t);
219 / -204800 1/2 3200
--- ln(1 + |1 - exp(-------)| ) + ----,
32 15987 / 73
219 / -204800 1/2 3200
--- ln(-1 + |1 - exp(-------)| ) + ----
32 15987 / 73
> evalf(%);
48.57933778, -48.57930791 + 21.50027473 I
> dpt:=%[1];
dpt := 48.57933778
> err:=52 - %;
err := 3.42066222
>
> (subs(t=dpt, pos) - subs(t=0, pos)) / (dpt - 0);
15.42611858 ln(exp(14.19670145))
- 30.85223715 ln(exp(14.19670145) + 1)
- 15.42611858 ln(exp(0)) + 30.85223715 ln(exp(0) + 1)
> evalf(%);
-197.6148797
> errv:=198 - abs(%);
errv := 0.3851203
>
-
update
2003-02-21 16:16:29
OK, so I've been talking with raven667, and appearently he's busy moving servers, so no big deal. Currently, access to the httpd is restricted, but from what I've been told, the box will be back up soon.
In the meantime, please do not report any video download problems. They will be ignored. -
hm
2003-02-21 15:57:51
Alright, I'm not quite sure what's with raven667.org today -- I'll have to talk to the admin about it. I really, really, _really_ hope that it didn't get booted off the Web because of me...
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HAHAHAHHAHA
2003-02-20 15:34:19
I got my Physics Test IV back today.
score: 100%.
:D :D :D -
these days / I find / you're always on my mind
2003-02-19 14:12:09
When I went to go see "Mamma Mia!" (an excellent musical, by the way), the playbills handed out had a rather interesting article about the staying power of pop.
"Mamma Mia!", as you may know, is a musical using the work of ABBA. Other than that, it's basically a romantic comedy. The fact that it was produced using ABBA's music and lyrics as a backbone, though, is something pretty exceptional.
Why ABBA? Heck, for that matter, why pop music at all? According to the article. ABBA had -- correction, _has_ -- a kind of mystical staying power in the collective mind. A lot of people have the urge to get up and dance at the first strains of "Dancing Queen"; a lot more people can jive with the beat. Actually, at the performance I went to, audience members DID start dancing during the encore, when the cast members and pit performed "Dancing Queen" again. Quite a spectacle.
Why am I mentioning this?
I've fallen prey to that infectious influence of pop. Over the past few weeks I've been listening to Kylie Minogue's new tracks -- stuff I once disdained as junk.
I can't explain why, but this stuff has become some pretty good junk to me. The kinds of visuals that they stir up are just so _strong_. I can't listen to Kylie's "On A Night Like This", "Tight Rope", or "Fragile" anymore without storyboarding a Macross Misa Hayase/Hikaru Ichijyo romance video in my head.
Then again, I've always wanted to do a video like that, so maybe that's the reason. Unfortunately, it's quite distracting when you have _another_ AMV to work on.
Well, whatever the reason, I'm addicted to this stuff. And I don't feel guilty for it.
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