Maths

[max_nhk]

If you've ever felt bad about your maths, look at these.

[reuber1]

Wow. Just wow. I won't say too much, since I never had trig, but some of those are just plain dumb.

[Ned]

Bwahahahaha... Thanks for that laugh, Max!

I hope you don't mind me reposting those pictures, so everyone can see them easier...

http://mediamainline.com/temp/maths/pic11337.jpg
http://mediamainline.com/temp/maths/pic12287.gif
http://mediamainline.com/temp/maths/pic15457.jpg
http://mediamainline.com/temp/maths/pic27753.gif

[Navian]

oh boy.....

Since I've taken trig, statistics, and physics math. But after looking at those (which was kinda funny) I feel as though my IQ had just dropped several points. :(

[Ned]

Some of them are rather ingenius... I like the six=6 and the root 2 over 2 ones. ;)

[Ghastly]

Another :cool: :D
http://img447.imageshack.us/img447/8691/limitvo3.gif

[Ned]

Heh heh heh...

[cjoe]

lol. i've completely forgotten all my maths from school, but those are just hilarious!

[cjoe]

I did once write a poem on metaphysics for a whole maths exam though. I had no idea what so ever.

[max_nhk]

Bwahahahaha... Thanks for that laugh, Max!

I hope you don't mind me reposting those pictures, so everyone can see them easier...



No problem, got it from a friend anyway. Stuff like these are the best med.

[max_nhk]

Another :cool: :D
http://img447.imageshack.us/img447/8691/limitvo3.gif

Einstine said simplicity is the essence of wisdom. So these are genious we're look at!

[Samakimoto Graphics]

Max, I was actually trying to work out the third one "find x", and realised I'd forgotten how.

Very funny.

[SnowAngel]

This is hilarious! I'm totally not mathematically inclined, but still. FUNNY!

[Navian]

I'm totally not mathematically inclined...

My cousin is... Sadly he has a Masters degree in Mathematics.

[max_nhk]

Just need to know the standard formula for a right angle triangle.

x.x = y.y + z.z
x.x = 4.4 + 3.3
x.x = 16 + 9
x.x = 25
x = 5

Well, it's not like our lives depend on knowing this. :)

[Ghastly]

Just need to know the standard formula for a right angle triangle.

x.x = y.y + z.z
x.x = 4.4 + 3.3
x.x = 16 + 9
x.x = 25
x = 5

Well, it's not like our lives depend on knowing this.



It would if you had only 5 hours to build a fence between two other fences that measured 3 and four metres at right angles to each other... and you could only construct and build at a rate of 1 meter per hour where cutting any excess would increase the time it takes you...and that if you didn't fully enclose yourself in this enclosure then lions would get through and eat the tigers that are trying to eat some other animals that wanted to eat YOU!...if there were no tigers you'd be dead...you gotta prepare for everything you see? :cool:


My cousin is... Sadly he has a Masters degree in Mathematics.

sadly? :confused: CAD and Maths are like rhubarb and custard!

[Navian]

CAD and Maths are like rhubarb and custard!

Well, somewhat..

There is some math involved in drafting, but its not too intense, mostly ft/in/cm/mm conversions, spacing, marking a distance away from certain things, and some scaling of models to fit dimensionally to paper (1"=20' ect..) but it is nothing what the engineers usualy have, they have those numbers already before I start drawing (sometimes).

[PrintDriver]

You don't even need to do the math on a 3-4-5 right triangle...

But those were all really funny. Thanks.
:D

[Ghastly]

you do if no-one told you about the 3-4-5 triangle :D

[max_nhk]

Actually photoshop can help solve the 3-4-5 triangle problem.

[cmont]

Zombo made that possible --^

[Ryan8720]

My calculus teacher actually had the Find X triangle on hanging on the wall.

[LeftBrain Artist]

Speaking of math problems,

A friend of mine just asked me to help him figure out how to make a dodecahedron (12 pentagonal faced polygon) box out of brass and glass. Evidently he plans to construct the framwork (vertices and edges) from brazed brass strips and is having "difficulty" determining the angle the ends of the strips should be (where three meet to form a vertice).

I told him I would look into it, did some google searches. Holy geometry, batman. There's some wicked math involved with that problem. I'm thinking I should tell him to try something a bit easier, like herding cats.

[Ghastly]

It's actually a pretty cool problem that LBA!...you can actually wiki the answer for him http://en.wikipedia.org/wiki/Dodecahedron (he wants the dihedral angle(the angle between one face and another (or the angle at an edge))...and it says what it is to the right)...You've got me trying to derive the solution for myself now though :D (but it's bloody awkward trying to solve it without being at my desk...so I won't finish till later )


*edit* actually reading your post...the wiki solution probably isn't what he's looking for but I'll probably post something after I've had some sleep

[Ovaltine]

Here's a math question my mom (who is a math teacher turned librarian) always gave her 7th graders at the beginning of the school year.

If a chicken and a half lays an egg and a half in a day and a half, how many eggs can 3 chickens lay in 3 days?

[Ghastly]

discounting the dead chicken, (the dismembered one), and the egg that always cracks whilst being laid...one chicken makes 2 *full* eggs in 3 days... 3 chickens make 6.

[Ovaltine]

Actually 3 chickens make 6 eggs in 3 days because there are only 2 time periods.

[Ghastly]

that was my answer: one chicken makes 2 *full* eggs in 3 days... 3 chickens make 6

[Ovaltine]

Right, for the wrong reason :P

[Ghastly]

wrong reason? :confused: :D

hmm..half a chicken isn't laying anything (apart from laying dead)...so we have one chicken who can produce 3/2 eggs in 3/2 days...half an egg isn't really an egg...it can be considered waste...and thus it takes a chicken 3/2 days to lay just one egg
By this reckoning, a chicken will lay 2 eggs in twice that period, ie: 3 days...and since there are 3 chickens we end up with six eggs no?

[Ovaltine]

Funny reasoning, mom would be in stitches.

There is no waste though...by your reasoning there should only be 4 whole eggs.

1.5 days + 1.5 days = 3 days = 2 time periods

1 chicken + .5 chicken + 1 chicken + .5chicken = 3 chickens

3 chickens times 1 time period = 3 eggs

3 eggs times 2 time periods = 6 eggs

[Ghastly]

By my reasoning there should be 6 eggs (If 3 chickens lay the same amount of eggs...how can they produce 4?) :D As I said...a chicken takes 1.5 days to lay 1 whole egg...to lay 2 it would take 2(1.5) = 3 days. If simultaneously 2 other chickens were doing the same thing then we'd have 6


I think the nature of the question is such that though you can reach 6 via rote computation... ie:

3/2 chickens =3/2 eggs
2(3/2 chickens) =2(3/2 eggs)
3 chickens = 3 eggs
3 eggs = 3/2 days
3 days = 2(3/2 days) = 2(3 eggs) = 6 eggs

...it was designed to be considered carefully before the computations take place ie: what can half a chicken really lay? ...what is half an egg? ;)

Also if you consider my solution all I've done is drop half a chicken and also half the egg such that if:

3/2 chickens =3/2 eggs
2/3(3/2 chickens) =2/3(3/2 eggs)
1 chicken = 1 egg
3 chickens still = 3 eggs :D

so the end result cannot be 4 eggs since the equality stays the same throughout :cool:

[Ghastly]

LBA don't know if your friend is interested but I've found the interior angle between vertices of a dodecahedron to be 121.717... degrees (he'll have to take this on trust because no-one has checked my working...tests in 3D seem to show that it is correct though)...the dihedral angle (the hinge angle) measures 116.565...degrees (the derivation from the author at wikipedia is neater than mine :( ) As your friend probably knows the plane angles at the vertices of a pentagon measure 108 degrees

[LeftBrain Artist]

LBA don't know if your friend is interested but I've found the interior angle between vertices of a dodecahedron to be 121.717... degrees (he'll have to take this on trust because no-one has checked my working...tests in 3D seem to show that it is correct though)...the dihedral angle (the hinge angle) measures 116.565...degrees (the derivation from the author at wikipedia is neater than mine :( ) As your friend probably knows the plane angles at the vertices of a pentagon measure 108 degrees


Yeah, the first thing I did was google it, and found the wikipedia entry with the dihedral angle - that helped. Your interior angle should be pretty close, Looking at a vertice from directly above, the 3 angles appear roughly equal (Looking at a 12-sided die for reference) - which would make them about 120 degrees each.

Unfortunately thats not the answer I'm looking for. Since you know what it looks like: Each vertice forms a point that is the meeting point of 3 edges of 3 adjacent pentagons. Now imagine that these eges are two points on a triangle, the third point being the true center of the dodecahedron (and the center of the theoretical sphere in which the polygon is inscribed). So the three edges are actually the ends of planes which recede to the center point of the polygon. Where three of these planes meet at a vertice, that's where I need to determine what angle they meet at. Once that is known, 30 identical "cross members" i.e. the edges can be constructed out of brass. The ends of the cross members will feature an acute angle so that when three are brazed together, they form a correctly aligned vertice.

I think that angle is around 56 degrees. Really though, the beauty of metal is its malleability. Once you start assembling the pieces of the dodecahedron, your friend will be the hammer and some carefully prepared jigs. Even if you nail that angle down to the 5th decimal place, even the most skilled metal smith will ecounter error margins of plus or minus a few degrees with the actual pieces.

This friend of mind knows a guy who knows a guy who supposedly will braze these for him. I doubt he has any idea how tricky its going to be.

[LeftBrain Artist]

...You've got me trying to derive the solution for myself now though

Don't you hate that. I have a hard time giving up on things like this.

[Ghastly]

Hate it? nah :D I enjoy having something to wrestle with...I haven't done any work on polyhedra or the platonic solids before so it's more a process of discovery than it is anything else.