MarkT

Yes, correct.

Solve simultaneously: 3a + b - c =10, a - 2b + 3c = -7, 2a + 3b - 2c = 15 a = ?, b = ?, c = ? Bonus points for solving it via a matrix method.

Perhaps you're the one on the left: He never actually drinks the wine.

Deep breath... and: A = (2+sqrt(5))^(1/3) + (2-sqrt(5))^(1/3) A^3 = (2+sqrt(5)) + 3.((2+sqrt(5))(9-4.sqrt(5)))^(1/3) + 3.((2-sqrt(5))(9+4.sqrt(5)))^(1/3) + (2-sqrt(5)) = 4 - 3.[ (2+sqrt(5))^(1/3) + (2-sqrt(5))^(1/3) ] = 4 - 3.A A^3 + 3.A - 4 = 0 (A-1)(A^2+A+4) = 0 A = 1. I'm not going to bother with the imaginary roots. Good enough?

None of the above. As it happens, I woke up this afternoon.

I don't believe so, at least I've never seen the floor (or signum) functions defined so. I'd say that the derivative of sign/signum is the delta function. The floor function, as far as I know, is the greatest integer less than it's argument. It woud take a strange function to differentiate to that. By the by, here is a wonderful place to go for information on functions of all kinds. Very interesting stuff here. The two attached sites Mathworld and Scienceworld are effectively encyclopedias of mathematics and sciences (paritcularly physical sciences). They can be quite handy for doing homework.

sgn( x ) is defined as -1 for x<0, 1 for x>0 and 0 for x=0. It's also known as 'the sign function' or 'signum'. It has an approximately equivalent definition of x/|x| if you prefer it (gets a little strange for x=0 though)

Polar-cartesian substitutions x = r * cos( t ) y = r * sin( t ) x ^ 2 + ( y - 3 ) ^ 2 = 9 r^2 * cos(t)^2 + r^2 * sin(t)^2 - 6 * r * sin(t) + 9 = 9 r^2 * ( cos(t)^2 + sin(t)^2 ) - 6r*sin(t) = 0 r^2 - 6r*sin(t) = 0 r = 6 * sin(t) for 0 <= t < pi/2

dy/dx = sgn(x) / ( 2 * sqrt( |x| ) ) f(x) = x^0.5 (x>0) = (-x)^0.5 (x<0) f'(x) = 0.5*x^-0.5 (x>0) = -0.5*|x|^-0.5 (x<0) = sgn(x) / 2 * x^-0.5 = sgn(x) / ( 2 * x ^ 0.5 ) = sgn(x) / ( 2 * sqrt( |x| ) )

Hey, sure! Seven and a half million posts from now we could be right up there!!! I think that's worth three exclamation marks.

Akya - Oh well, if nobody else is going to guess: f(x,y) = x^2 + 4xy + sin y + y^2 (df/dx)y = 2x + 4y (df/dy)x = 4x + cos y + 2y

Hey, now there's an idea. Wonder why I didn't think of that.

My sympathies to your mother, Tim. When does this happen? Meetings and so forth? (not that I want to pry, of course). If it is mainly meetings, you could try and get a member of the assistant staff to attend them (ask them to take minutes, perhaps?) If hidden recording devices are out, have you considered visible ones? Taped logs of meetings, CCTV security... Also, it's not neccessary to actually record anything. If the other people just think they're being recorded, they're probably less likely to say anything untoward. Also you could try investigating what the penalties for leaving before the given date would be (presumably breach of contract?) Well, these I what I can think of immediately. I could try and ask around in the legal department of the university here, if you'd like? On the subject of doing funny things with bank accounts, let me just emphasize I think that this would be a bad thing to do. Whatever you plan to do from this point forward, being involved with anything of that nature is unlikely to be helpful. Also, that does give you another recourse, to whatever your local equivalent of the Inland Revenue or Companies House is.

Curu, I realise that isn't what you said per se, but that was the implication I got from it. My post was simply for the purposes of clarification

On a point of information: Tony Blair didn't introduce tuition fees in England, he just has this great idea about letting universities charge as much as they like. Not that I blame the universities, of course, when Mr. Blair's other great idea was removing most of their government funding... Also, the reputation of the university one goes to does still make a difference in the UK. There are many well-respected ones and a few not-well-respected ones. Not necessarily fair, but it's still the case.

Already at university, studying for a degree in Computer Science.

Or perhaps it was written by a real hacker trying to spread paranoia and confusion amongst the - hmm, let's say two - people in the world who might believe this. Who else thinks that 'Linyos Torovoltos' has a nice ring to it though?

Anyone find it slightly worrying that ZeZar feels it's neccessary to include the statement 'Not kill them, just talk'? www.hasbro.com will take you to them.

They're called caltrops, if you're talking about what I think you're talking about...

To me (depending on the person speaking, of course) American English sounds coarser; more simplistic and less subtle than (English) English. (Again, no offence )

I don't think 'top of the morning' is used here 'seriously' any more. Perhaps when someone is trying to play up to the British stereotype. I'll be back here later...

Friday the 13th will have an effect on some people, I think, due to the power of negative thinking; I don't believe the day itself is intrinsically unlucky.

The 'ballad' from The Hunt for Red October.

'deus ex machina' I may as well say something on this before someone else does (or, even worse, nobody does) It's the term used, particularly when referring to dramatic arts, for the force, person, or device that intervenes to fix up loose ends (or gaping holes) in the plot. Literally, (a) God from the machina - a machine used to suspend actors (representing the Gods) above the stage in Greek theatre. And the winner of the most use of parentheses in a short post goes to...

I played the old Duke Nukem games (2D EGA graphics, remember?) They were moderately fun for a time.