[pne]

Quote:

Originally Posted by Techno Rocker /img/forum/go_quote.gif Well here we go: 1. They are perpendicular I just need to right the formal proof 2. This problem was too easy. 3. This one, is unsolvable. Now because I'm going for the prize I'll post my answers tomorrow.

hmm really. why don't you post them if you can't solve one out of three anyways? Did you read my post? Question 2 & 3 should be solved similarly (assigning a coordinate system, finding plane normals and using dot product) if you used this method 3 is solved exactly like 2 but less work because you are already given two vectors. Or maybe I am overthinking the problem...i'm pretty sure we learned vectors and dot product in highschool... if noone posts answers to this by next monday, i'll be done my after-finals partying by then and try to solve it.

 

[deathklok]

Quote:

Originally Posted by Rock&Roll Ninja /img/forum/go_quote.gif No, they use computer programs to track these figures. There is no magical stock broker trapped in a closet who uses Euclidian geometry to mark the trade values of RMB. Regardless your cache of 'engineers, bankers, and brokers' still represent far less than 1% of the poulace, which I argued was the percentage of human adults who understand the mechanics and use higher mathemeatics* *Any joe can figure their cost of gas usage on their new car for Xmiles. So yes he is using an advanced Algebraic solution (even if he doesn't know it). Thus the point I make of understanding the mechanics. Much like you don't need a chemistrty degree to light a match. Or a medical degree to diagnose a compound fracture.

Somebody has to know the math to check the software, or create it in the first place. And you'd be surprised how many engineers still use slide rules and basic calculators.

 

[Techno Rocker]

Quote:

Originally Posted by pne /img/forum/go_quote.gif hmm really. why don't you post them if you can't solve one out of three anyways? Did you read my post? Question 2 & 3 should be solved similarly (assigning a coordinate system, finding plane normals and using dot product) if you used this method 3 is solved exactly like 2 but less work because you are already given two vectors. Or maybe I am overthinking the problem...i'm pretty sure we learned vectors and dot product in highschool... if noone posts answers to this by next monday, i'll be done my after-finals partying by then and try to solve it.

The reason #3 is unsolvable is:

1. They are to vague in the problem

2. AD and BC1 are parallel and exist on different planes.

If they had said what angle do they create if they overlap and actually intersected then yes, it would be easier. I did not read your post because I simply overlooked it.

Question 2 deals strictly in tangents and cosines finding angles and then calculating the answer. Its really quite simple.

And yes really. I am going to post them tomorrow and if other people find them to be wrong, and they can provide a legitamite reason why, so be it! If I'm wrong I like to know where and how I can fix it. I try not to be prideful that way. I'm not going to post the answers just so some idiot can take my work and win the prize. End rant.

I took this as a challenge and I learned things by just trying to go for it. Even if my answers are wrong, I believe that I learned enough to justify the time spent. Good Night.

T.R.

 

[pne]

Quote:

Originally Posted by Techno Rocker /img/forum/go_quote.gif The reason #3 is unsolvable is: 1. They are to vague in the problem 2. AD and BC1 are parallel and exist on different planes. If they had said what angle do they create if they overlap and actually intersected then yes, it would be easier. I did not read your post because I simply overlooked it.

it is not unsolvable. what level of math are you at right now? (not trying to belittle you just curious) The problem is quite clear and AD/BC1 are not parallel, if they were the angle would be 0. you can find angles between lines in space that exist on seperate planes. I wish i had kept my linear algebra textbook because i could find the proof for 1 and solve 2/3 with a few reference notes. It doesn't seem to me like this problem is elementry or that you can reason your way though it. The proper way I see of solving it requires more than just a simple cosine law.

I know there are a lot of math whizes on head-fi, I've seen a lot of calculus problems solved on here that I wouldn't have a clue on how to tackle. If only someone would chime in and confirm the theory if nothing else. So far we've only had two people who have made an attempt to solve it, and me who has just speculated on the method to solve it (yes I'm quite lazy). For all those people who posted that this was an easy problem, what say you?

 

[Techno Rocker]

I checked over my math again and pne you were right. They are not parallel. But I know I'm right about my answers for one and two.

At present I simply lack the knowledge to solve number three.

If anyone can shed some light on this or know how to do it please chime in. I'm very keen to see whats going on with this problem.

T.R.

 

[Rock&Roll Ninja]

Quote:

Originally Posted by Techno Rocker /img/forum/go_quote.gif I checked over my math again and pne you were right. They are not parallel.

Told ya so

 

[Techno Rocker]

Quote:

Originally Posted by Rock&Roll Ninja /img/forum/go_quote.gif Told ya so

Rock&Roll Ninja:

No you did not. Please don't take credit for what he (pne) has revealed to me.

And again, the fact that I was wrong about that is great! It forced me to go back and check all of my problems and in that process, I found out that number three is solvable, but the math required for it is just way over my head at the moment. At least I tried.

My answers:

1. In the proof that you make you must prove that A1C and AC exist on the same plane, from there everything just follows from that because if they exist on the same plane, and AC is _|_ to BD then A1C must also be _|_ to BD.

2. This one was the easiest of the three. It involves many long steps find tangents and co-sines (if you want my calculations pm me with an email address and I'll send them to you) to get the that angle formed between the two planes. We can do this because both of the planes intersect at the line BD. I turns out that that angle between them is 90 degrees.

Again if you find anything wrong with what I have said and you show what it is and how to correct it than please do so. I'm here to learn, not show off my math skills. If it was merely to show off, let me tell you, I have plenty of other things I'd rather be doing. Again I'm here to learn.

pne:

Thanks again for your help

T.R.

 

[Konig]

Quote:

Originally Posted by jinp6301 /img/forum/go_quote.gif well its not that hard, and I'm pretty sure that they chose an easy one from an not that prestigious university but check out University of Tokyo's entrance exam, or if you want an easier one, the National University of Seoul's (South Korea) entrance exam. I got a 1540 on the SATs (the old one) and I could only do like half of the questions on the NUoS math test. America still hasnt figured out that theyre so far behind a lot of the industrialized Asian countries in education.

its not how much you know, its how much you can create for others to know.
Asia come up top in international standardized test but they still havent figure out why they cant churn out inventors, nobel prize winners, patent holders like the west.

 

[Exit Pupil]

Quote:

Originally Posted by pne /img/forum/go_quote.gif I know there are a lot of math whizes on head-fi, I've seen a lot of calculus problems solved on here that I wouldn't have a clue on how to tackle. If only someone would chime in and confirm the theory if nothing else. So far we've only had two people who have made an attempt to solve it, and me who has just speculated on the method to solve it (yes I'm quite lazy). For all those people who posted that this was an easy problem, what say you?

yeah, good point.

so what is the answer? i'm a wee bit dissappointed, it is designed for teenagers after all

the problem must be harder than expected, i thought solutions would be flooding in within minutes of my initial post

 

[Kirosia]

Quote:

Originally Posted by Rock&Roll Ninja /img/forum/go_quote.gif They're in Asia making stupid pointless tests to distract the rest of the world while they quietly steal our chocolate

S**t, he's on to us...

Anyways, I hate/suck at math so I looked at the first one and said screw it. I'm a dumbass. (nah, just a lazy person)

Quote:

The English one must be from a community college, or something extremely easy, because I knew how to do that in 8th grade.

I always considered community college to be in the same realm as your average state college (in regards to academic difficulty). My friends who transferred/go to four year schools say stuff's even easier sometimes. (Makes sense, since CC is theoretically supposed to prepare you for survival at a real school) We're not all taught first grade subjects like many would think. Though I do miss those scratch 'n' sniff stickers...

 

[Exit Pupil]

an aside - i read that Einstein was so daft at maths he had to employ an undergrad to do his calculations for him. read it in 'a short history of nearly everything' by Bill Bryson , a hilarious book by the way.

 

[dj_mocok]

Damn, I seriously can't even solve the English university question one. Is it only me?

 

[saint.panda]

Quote:

Originally Posted by Exit Pupil /img/forum/go_quote.gif an aside - i read that Einstein was so daft at maths he had to employ an undergrad to do his calculations for him. read it in 'a short history of nearly everything' by Bill Bryson , a hilarious book by the way.

Well, he wasn't particularly "daft at maths" although he did let his wife, a brilliant mathematician, do a lot of the mathematical foundation for his relativity stuff. Just to put things into relation, to completey understand the math behind general relativity, not just working with it or partially getting it, you more or less need a master's degree in math or theoretical physics, and that was several decades ago. So basically he had an idea and let her calculate it through to see if his hunches were correct. Really convenient.

 

[Techno Rocker]

They announced the answers and winners:

http://www.rsc.org/AboutUs/News/Pres...CompWinner.asp

They don't show the proof but I was glad to find out that it was indeed a kite shape because that was what I based my calculations off of. I got number two right and unfortunately I couldn't solve the third. Just did not know the math for that. The third question, I believe, was the hardest.

Very interesting stuff...

-T.R.