| |
| |
| |
|
Page: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Comments:
<0> n0other: although a better argument for showing that the second function is not surjective is 'but we never get the real number 0, so it's not surjective' (the example is arbitrary of course)
<0> i.e. point out a counteraxample for the surjectivity property
<1> I see
<2> i took -1 in my example
<0> Killer666: pick another.
<2> every negative real would work
<0> Killer666: oh, you're discussing a different function.
<2> ha
<3> Hello
<2> hey
<3> I am really rusty on my trig, simple trig like how to solve arcsin 1/2, i need an easy way to remember the radian circle
<4> tommmied, http://en.wikipedia.org/wiki/Image:Unit_circle_angles.svg ?
<5> http://tinyurl.com/gwt9h
<3> thanks
<3> is there any easy way to remember that
<6> do lots of math problems
<3> haha
<3> is there a site that has a lot of problems
<6> probably. ask the google
<7> tommmied: www.microsoft.com
<8> ?yow
<5> All I can think of is a platter of organic PRUNE CRISPS being trampled
<5> by an army of swarthy, Italian LOUNGE SINGERS ...
<9> A jeep can carry at most 50 gallons of fuel total in its tank and in cans. The cans can be left along the road for future use. The jeep gets 10 mpg, and needs to travel 1000 miles one way. How should it leave gas along the route to get itself to the destination with a minimum amount of fuel?
<0> old problem.
<10> but i forgot the solution :)
<11> I have made a Matrix cl*** and have a multiply function that works with 2D matrices, but the cl*** also supports 3D matrices, how would multiplication of a 3D matrix work?
<0> you go the last 500 miles in one trip, the 500/3 miles before that in 3 trips, and so on.
<10> int-e : any problem you know for a while is "old" :-P
<9> is it related to the sparrow flying back and forth between the two trains?
<11> hi quilzo
<12> yo Aardwolf ^^
<12> ask it, I want to know too
<10> but how do you prove the optimality ?
<11> I did right before you joined :)
<12> damn
<11> I'm not awaiting the answer
<11> *errrr
<0> kmh: by looking at the number of times you cross a certain point.
<11> I mean, I'm noW awaiting the answer
<12> haha
<12> !gra... ow nvm ;)
<11> :D
<12> you COULD figure it out for yourself, I think
<11> yeah, I was thinking up something...
<11> but it would require 3 operands instead of 2
<11> :(
<12> sux
<9> int-e: so, i need to work backwards?
<11> or maybe something recursive
<11> where the multiplication of 2 3D matrices, boils down to multiple multiplications of 2D matrices :)
<12> hmmm
<11> like, slice by slice
<12> not a bad idea
<12> don't know if it's "doable" though
<12> or if it's allowed
<0> kmh: at 500 miles you need 50 gallons of fuel. so from that point on you need at least three trips (two forward, one backward). making more trips is bad, because it costs additional fuel. 3 trips get you to 500 + 500/3 miles from the goal. At that point you need at least 100 gallons, so 3 trips aren't enough; you need 5. and so on.
<0> chessguy: right, you'll have to work backwards
<12> te vroeg gestopt me latijn-wiskunde ^^
<11> I got it: I'll let it return an error if you try to multiply non-2-dimensional matrices
<11> hehe, ik ben van latijn-wiskunde naar wetenschappen-wiskunde 8 overgegaan :)
<12> haha
<9> whoah, you lost me
<0> chessguy: it's a very technical proof because there are many optimal solutions.
<12> Aardwolf, deej l-wis8 en nu tso-informatica ^^
<12> thuis...
<9> if you have 50 gallons of fuel at the halfway point, you only need one trip to get to the endpoint
<11> dus eigelijk een heel jaar vakantie? :)
<12> uh neej
<12> tis moeileker dan ik dacht
<12> als in... school =/= examencommissie -_-"
<11> ja, examencommissie klinkt natuurlijk "strenger" dan school
<12> "klinkt"... hmm
<11> of is
<12> idd
<0> uhm. could you stick to english, please?
<12> sorry
<12> all books from 1985...
<11> I thought math was an universal language :(
<12> int-e, how do you multiply 3d-matrices ?
<11> quilzo, IT books from 1985? :S
<12> Aardwolf, yup
<11> wtf
<12> yup
<0> chessguy: solve the problem for 512 miles.
<11> in the IT world, that's like 2 centuries old!
<0> quilzo: my matrices are 2d
<11> int-e, how would you multiply two 3-dimensional tables of numbers?
<0> there are tensors but I don't know how they work. I never needed them.
<12> damn
<11> ok, I'll wikipedia for tensors
<9> maybe i should start by solving it for a really small number
<11> (if to wikipedia is a verb)
<12> haha
<12> to wiki :)
<11> :)
<0> chessguy: something a bit above 500 will be instructive. say, 512
<0> chessguy: you need 53.6 gallons for that.
<9> total?
<13> I'm having problems proving that (1-cos(x))/sin(x) is the same as sin(x)/(1+cos(x)). Could someone help me in the right direction?
<0> chessguy: for 512 miles, yes.
<12> (1-cos(x))*(1+cos(x))
<9> but if i don't know how to solve it for 1000 why would i know how to solve it for 512/
<9> ?
<12> chessguy: I think by just doing it, you'll figure out why
<9> by doing something i don't know how to do?
<12> yes
<9> riiiight
<12> what's the "***ignment" ?
<0> chessguy: because it's slightly simpler :)
<0> chessguy: and up to 500 miles the problem is boring.
<12> you need x gallons of fuel to get somewhere... and what was the rest?
<9> so for 512, i need to have 25.6 gallons at the 256-mile point
<13> quilzo: ok, thanks
<9> quilzo: A jeep can carry at most 50 gallons of fuel total in its tank and in cans. The cans can be left along the road for future use. The jeep gets 10 mpg, and needs to travel 1000 miles one way. How should it leave gas along the route to get itself to the destination with a minimum amount of fuel?
<12> norton: did it help you?
<0> chessguy: why? the tank still holds 50 gallons
<0> chessguy: well, yes.
<9> at least 25.6
<0> chessguy: but the 256 miles point is not interesting.
<13> quilzo: I don't know yet, I hope so :)
<9> but the 500-mile point in the original point is?
<12> norton: i'll try it too
<9> oh, right, ok
<9> so i need 50 gallons at the 12-mile point
<0> yes
<14> Is the 4th root of ten a real number?
<9> i got that far in the original problem
<0> newbiedoo: two of them are
<9> but i still don't know what to do from that point
<0> chessguy: this isn't possible in one trip.
<14> That would also be known as 10 ^1/4
<0> chessguy: because in one trip, you'll get at most 48.8 gallons to that point.
<12> norton: it's super-easy :p
<9> where are you getting 48.8 from
<0> chessguy: so you need to make one trip, a trip back, and another trip, covering the 12 miles three times
<0> 50-1.2
<9> oh, right
<0> so you need at least 53.6 gallons.
<13> quilzo: haha. ok :p
<12> norton: do you have it or not?
<0> on the other hand 53.6 gallons suffice - fill the tank, go the 12 miles, unload 1.2 gallons, go back, fill up the tank, and then make a single trip across the desert, picking up the 1.2 gallons on the way.
<9> so i should go to the 12-mile point, leave 1.2 gallons there, go back, and start over
<9> ok
<14> int-e> What do you mean two of them are? I am supposed to indicate if the solution to a problem is a real number and if so, then simply the equation and declare what that number is. I tried to write it as the 4th root of 10 and also as 10^1/4 and Hawkes won't take it.
<9> now let me attack the original problem
<0> this solution extends easily to 500 + 500/3 miles.
<13> quilzo: I get that (1-cos(x))*(1+cos(x)) is the same as (sin(x))^2. But I don't see how I can get from (1-cos(x))/sin(x) to sin(x)/(1+cos(x))
<9> so you know that you need three trips to get 50 gallons to the 500-mile mark, right?
<12> norton, check query
<13> quilzo: what's that?
Return to
#math
or
Go to some related
logs:
fedora drivers for zew1601
8280ca/cam Ac'97
net.ipv4.netfilter.ip_conntrack_tcp_timeout_established
colspan with css
lisppaste howto
ERROR 2006 (HY000) at line MySQL server has gone away
#perl
#linux
sendmail what is dnl
ERROR 2002 HY000 Can connect to local MySQL server through socket /var/run/mysql
|
|
