Search found 28 matches

Mon Jun 01, 2009 6:34 pm UTC
Forum: School
Topic: Xbox/Wow Style Achievements
Replies: 13
Views: 1471

Re: Xbox/Wow Style Achievements

Hmmm your A level students aren't likely to like it (speaking as an AS student). Year 7 might like it but after year 9 they will probably be too jaded for it. That said it we like sweets and will put up with (and maybe even participate in) anything if there is a high probability of them :) I'm teac...
Mon Jun 01, 2009 4:53 pm UTC
Forum: School
Topic: Xbox/Wow Style Achievements
Replies: 13
Views: 1471

Re: Xbox/Wow Style Achievements

Sadistic Humor wrote:Achievement Unlocked: Not looking like a prostitute.

It would almost be worth the stern costernation of administration to put that into writing. Also, sad that it's come to that though.
Mon Jun 01, 2009 4:24 pm UTC
Forum: School
Topic: Xbox/Wow Style Achievements
Replies: 13
Views: 1471

Xbox/Wow Style Achievements

I'm a high school math teacher, and in the interest of promoting student involvement and participation, I want to implement an achievement system similar to the ones used on Xbox Live or in World of Warcraft. (They'll spend hours working on those, but can't spare 15 mins for extra help...) For the s...
Thu Jan 29, 2009 6:29 pm UTC
Forum: Mathematics
Topic: The continuous elevator
Replies: 15
Views: 1970

Re: The continuous elevator

I clearly see now that fixing either the spawn time or the speed and varying the other has the same effect on the problem. I didn't get quite that meaning when I read your earlier post.
Thu Jan 29, 2009 5:05 pm UTC
Forum: Mathematics
Topic: The continuous elevator
Replies: 15
Views: 1970

Re: The continuous elevator

We are told the speed the dots are spawned is a constant 1/sec. This is independent of the speed of our elevator. If you'll allow me a discrete example to illustrate why I'm having trouble with this idea... Imagine n cash registers that begin empty. Every minute a customer arrives at an empty regist...
Thu Jan 29, 2009 3:52 pm UTC
Forum: Mathematics
Topic: The continuous elevator
Replies: 15
Views: 1970

Re: The continuous elevator

One dot is added at 0. Then dots are added, two at a time, at 0.9 and 1.0, every 0.1 seconds. This just happens, randomly... It is never in the interests of the elevator to head down to the 0, if the goal is to reduce the average wait time of dots after they are spawned. Yeah, but the P(X>.9) is on...
Thu Jan 29, 2009 2:51 pm UTC
Forum: Mathematics
Topic: The continuous elevator
Replies: 15
Views: 1970

Re: The continuous elevator

Since the points are truly random, I think the best method is to just travel back and forth from 0,1 over and over. The worst case scenario is a wait time of 2/v, but the average should be no worse than 1/v and I'd wager most wait times are less. I just don't have the time to try and nail down an ac...
Tue Jan 27, 2009 6:53 pm UTC
Forum: Mathematics
Topic: objects that we'd like to hold, but can't in this universe
Replies: 41
Views: 6212

Re: Looking for a link for these 4 and 5 dimensional graphs

How has noone pointed to these? For all your non-orientable drinking requirements.
Mon Jan 26, 2009 8:54 pm UTC
Forum: Mathematics
Topic: Polynomial problem
Replies: 8
Views: 1114

Re: Polynomial problem

Here's how this one goes: /snip What is r, the polynomial you get from dividing f by g. You obviously can't use the division theorem, and f is not irreducible as far as I can see. If, as you assert in the problem, the answer is a polynomial, then we know g divides evenly into f. That should simplif...
Thu Jan 22, 2009 2:57 pm UTC
Forum: Mathematics
Topic: Argh... what am I not seeing? (homework problem)
Replies: 14
Views: 1991

Re: Argh... what am I not seeing? (homework problem)

Token wrote:Change of variables: y=ex, solve for y as a quadratic, then take log for x.

Spoiler:
x = ln(2)?

Since ex is never zero I multiplied through the equation by it, then did the u substitution and solved the quadratic. Double checked on graphing calculator.
Thu Jan 22, 2009 11:47 am UTC
Forum: Mathematics
Topic: MATH PUZZLE!
Replies: 25
Views: 2372

Re: MATH PUZZLE!

Based on the receipts in my wallet, you round to the nearest cent, and if the subtotal ends in 0.10, 0.30, 0.50, 0.70, or 0.90, you round up.... I have a lot of receipts in my wallet.... Incidentally, at the Greenhouse Cafe, a cup of Tazo tea is $1.39, a bubble tea is$4.25, and a tomato basil mozz...
Wed Jan 21, 2009 10:45 pm UTC
Forum: Mathematics
Topic: MATH PUZZLE!
Replies: 25
Views: 2372

Re: MATH PUZZLE!

Assuming they each ordered the same thing and tax was not included in the price -- there were 3 of them, the total for the tea and sandwich was $6.01.$6.01 * 3 * 1.05 = \$18.94
Fri Jan 16, 2009 3:14 pm UTC
Forum: Mathematics
Topic: Line Integrals (Yeah, this is homework)
Replies: 7
Views: 942

Re: Line Integrals (Yeah, this is homework)

And this is what I've done so far: A = 2 \int 1 + {1 \over 3}y ds Now, using \int f(x,y) ds = \int f(x(t),y(t)) \sqrt {[x'(t)]^2 + [y'(t)]^2} dt We get 2 \int_0^{\pi \over 2} 1 + 10sin^3t \sqrt{(-90cos^2tsint)^2+(90sin^2tcost)^...
Fri Jan 16, 2009 2:33 pm UTC
Forum: Mathematics
Topic: Line Integrals (Yeah, this is homework)
Replies: 7
Views: 942

Re: Line Integrals (Yeah, this is homework)

$2 \int_0^{\pi \over 2} 1 + 10sin^3t{90sintcost} dt$
Applied a trig identity:
$2 \int_0^{\pi \over 2} 1 + 10sin^3t{45 sin 2t} dt$

Instead of using a trig identity can't that be simplified further to:
$2 \int_0^{\pi \over 2} 1 + 900sin^4t{cost} dt$
Tue Jan 13, 2009 11:43 pm UTC
Forum: Mathematics
Topic: Periodic function mapping to {0,1}
Replies: 17
Views: 1605

Re: Periodic function mapping to {0,1}

So, I'm looking for a periodic function f:\mathbb{R}\rightarrow \{0,1\} . Here's the caveat. I want the function to have some sort of variable periodicity -- say I want to generate a pulse every 1.5 seconds, but say at random the next pulse might come at t+.75 seconds. Here's the second caveat. It ...
Tue Jan 13, 2009 11:37 pm UTC
Forum: Mathematics
Topic: Beginner Stuff
Replies: 23
Views: 2381

Re: Beginner Stuff

Well, yes, but it's no longer a set. Sets don't have repeated elements. It's pretty bad notation on her part, but it's not worth arguing the point. (Seriously though, sets don't have repeated elements.) Sets don't have repeated elements, or a set with repetitions is equivalent to one with repetitio...
Tue Jan 13, 2009 7:58 pm UTC
Forum: Mathematics
Topic: common error in poker logic?
Replies: 17
Views: 2193

Re: common error in poker logic?

SlyReaper wrote:
GreedyAlgorithm wrote:The turn comes 7, the river comes 7. Now do you think it's less likely your opponent holds a 7?

Slaps down a pair of sevens on the table. Six of a kind! I win!

No... he has the uh, royal sampler.
Tue Jan 13, 2009 7:42 pm UTC
Forum: Mathematics
Topic: Beginner Stuff
Replies: 23
Views: 2381

Re: Beginner Stuff

My new College Algebra teacher told me "that is not always the case." Life lesson: Smile and nod, and use her definition of a function in her class . People in power aren't always right, but they can really mess up your GPA. Or understand that at a lower level a simplified definition was ...
Sun Jan 11, 2009 4:30 am UTC
Forum: Mathematics
Topic: Making a perfect venn diagram
Replies: 7
Views: 6050

Re: Making a perfect venn diagram

OK, I don't know how to do the markups to make the pretty math symbols, but I think I can explain it without. Let the left circle be the unit circle centered at the origin and the right circle be a unit circle with center (a,0). These circles intersect at x=a/2. Consider now only the semicir...
Sat Jan 10, 2009 5:15 pm UTC
Forum: Mathematics
Topic: "Drunk Driver" Problem
Replies: 7
Views: 1227

Re: "Drunk Driver" Problem

It is easy to see that one can go through the entire deck: Each ace can add 4 cards to the pile, each king can add 3, each queen can add 2, and each jack can add 1 for a total of 40 cards. Adding in the 16 face cards makes a total of 56 possible cards dealt. Why do you add in the 16 "face"...
Sat Jan 10, 2009 4:58 pm UTC
Forum: Mathematics
Topic: "Drunk Driver" Problem
Replies: 7
Views: 1227

Re: "Drunk Driver" Problem

Let's see, there's 52 C 7 ways to deal 7 cards. Of those 36 C 7 have no face cards, so 6% of the time you don't even drink... so sad. I think the easiest way to solve this would be to run a simulation, there are so many test cases that the math would get long and boring before I arrived at a solutio...
Sat Jan 10, 2009 4:53 pm UTC
Forum: Mathematics
Topic: "Drunk Driver" Problem
Replies: 7
Views: 1227

Re: "Drunk Driver" Problem

It is easy to see that one can go through the entire deck: Each ace can add 4 cards to the pile, each king can add 3, each queen can add 2, and each jack can add 1 for a total of 40 cards. Adding in the 16 face cards makes a total of 56 possible cards dealt. Why do you add in the 16 "face"...
Thu Jan 08, 2009 1:28 pm UTC
Forum: Mathematics
Topic: Stupid question, differentiation of absolute value
Replies: 4
Views: 1233

Re: Stupid question, differentiation of absolute value

As a general rule the absolute value is not differentiable because of the sharp point at zero... the limit of dy/dx is different from the left and right. If you break it up into a piecewise function and do the two halves seperately, then it usually works out ok. Disclaimer - Teaching HS has left me ...
Thu Jan 08, 2009 12:21 pm UTC
Forum: Mathematics
Topic: Prove that two curves in a square intersect
Replies: 76
Views: 6412

Re: Prove that two curves in a square intersect

If you're saying you want a homeomorphism between Im(c) ∪ Im(d) and the union of two lines with the same endpoints, you won't find it, since the former might actually have more (distinct) intersections than the latter. OK, but if it isn't possible for the former to have FEWER interesections than th...
Thu Jan 08, 2009 11:48 am UTC
Forum: Mathematics
Topic: Prove that two curves in a square intersect
Replies: 76
Views: 6412

Re: Prove that two curves in a square intersect

Is it necessary to prove that c and d are homeomorphic to lines with the same endpoints, or is that agreeably proven by someone else with a lot more education than me? Homeomorphism isn't the word you're looking for; you want homotopic. (The homeomorphism is obvious: take the inverse of one paramet...
Thu Jan 08, 2009 3:43 am UTC
Forum: Mathematics
Topic: Prove that two curves in a square intersect
Replies: 76
Views: 6412

Re: Prove that two curves in a square intersect

OK, as before feel free to correct me anywhere and everywhere. Is it necessary to prove that c and d are homeomorphic to lines with the same endpoints, or is that agreeably proven by someone else with a lot more education than me? If so the slope of the image of c is bounded by the interval (-1,1) a...
Wed Jan 07, 2009 9:54 pm UTC
Forum: Mathematics
Topic: Prove that two curves in a square intersect
Replies: 76
Views: 6412

Re: Prove that two curves in a square intersect

Well, as I've read the discussion it seemed to be, "oh we can't use the intermediate value theorem because we don't have functions". If as you say I've restated the original problem successfully with a function, then we can use IVT and the result should be trivial for someone with a little...
Wed Jan 07, 2009 7:55 pm UTC
Forum: Mathematics
Topic: Prove that two curves in a square intersect
Replies: 76
Views: 6412

Re: Prove that two curves in a square intersect

OK, if we're still trying to solve the original problem... Let x(t) be the horizontal displacement of c inside the square; x(0)=0 and there exists a t c such that x(t c )=1 Similarly, let y(t) be the vertical displacement of d inside the square. Now x(t) necessarily takes on every value from [0,1] e...