
Veteran

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Posted: 20 Jun 2006 21:20
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Okay, here's a math problem that someone sent me and I don't have time to help with it, so I thought I'd use you guys since you have nothing better to do...
Okay, imagine this stupid picture is a bridge.. the straight line is the distance between the two banks of a river, which consequently is exactly one mile wide. The bridge is exactly 1 mile and 1 foot wide, and touches the edge of each bank. How high is the bridge in the exact center from the water, assuming the water is just under the bridge?
_____________________ "Of all the tyrannies that affect mankind, tyranny in religion is the worst; every other species of tyranny is limited to the world we live in; but this attempts to stride beyond the grave, and it seeks to pursue us into eternity."
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Veteran

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Posts: 564 |
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Joined: 07 Jul 2003 |
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Posted: 20 Jun 2006 21:21
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p.s. The picture was for my amusement. I'm sure it's no help.
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Sergeant Major
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Posts: 5751 |
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Joined: 15 Sep 2003 |
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Posted: 20 Jun 2006 21:22
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Assuming the picture is to scale...about 2mm.
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Veteran

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Posts: 564 |
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Posted: 20 Jun 2006 21:28
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I hate you.
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Sergeant Major
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Posts: 5751 |
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Joined: 15 Sep 2003 |
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Posted: 20 Jun 2006 21:31
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I think I could actually figure it out if I wanted to. Something involving conics, vertices, covertices and stuff. That said, schools out so I'm not gonna use my brain.
Unless you hate me because I got it right.
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Veteran

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Posts: 564 |
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Joined: 07 Jul 2003 |
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Posted: 20 Jun 2006 21:33
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I have no idea what the answer is.. haven't even really looked at it closely. I copied what I wrote off paper. I've been working too much lately to give it much thought.
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Sergeant
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Posts: 363 |
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Joined: 25 Oct 2004 |
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Posted: 20 Jun 2006 21:39
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wat meanz math?
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Recruit
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Posts: 0 |
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Joined: 17 Dec 2003 |
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Posted: 20 Jun 2006 22:09
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That problem was olden when I was taking geo/trig. Just think triangle and you can solve it in seconds. Most people are fooled into trying to do chord math.
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Private First Class
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Joined: 09 Feb 2006 |
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Posted: 20 Jun 2006 22:22
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man i looked at it and was like "man i give up..."
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Private First Class
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Posted: 20 Jun 2006 22:44
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We need more information to solve this. So far we only know that the bridge is 1 mile 1 foot long (5281 feet) while the line of sight distance from end to end is 1 mile (5280) feet. These sound like pretty bizzare numbers because with such a small difference in distance the height should be absurdly small.
Anyway, it is impossible to determine the height of the bridge unless we know how the path of the bridge is defined. If this is a precalc/geometry problem it will probably say that the bridge is in the shape of a top half of an ellipse/parabola. If it is a calculus problem the bridge should be defined by some function. Simply using trig will not work on this problem since the extra 1 foot of length could be attributed to any factor (for all we know there is a bump in the bridge that adds an extra foot of arclength).
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Staff Sergeant
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Posts: 582 |
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Posted: 20 Jun 2006 22:56
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A civ eng would assume the shape of a catenary.
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Private First Class
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Posted: 21 Jun 2006 02:17
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Should we assume that the Earth is flat?
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Sergeant
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Posted: 21 Jun 2006 03:36
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| 97-Bravo wrote: |
Okay, here's a math problem that someone sent me and I don't have time to help with it, so I thought I'd use you guys since you have nothing better to do...
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I was going to solve the problem for you, but I take that to offense.
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Sergeant First Class
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Posts: 1645 |
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Joined: 11 Nov 2003 |
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Posted: 21 Jun 2006 16:34
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300
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First Sergeant
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Posted: 21 Jun 2006 16:47
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| [CGA]Sleestax wrote: |
That problem was olden when I was taking geo/trig. Just think triangle and you can solve it in seconds. Most people are fooled into trying to do chord math. |
It doesn't even seem to make sense, though; is it asking the height from the surface of the water to the bottom of the bridge, in the center? As we assume that the curvature in the pic is the bridge itself?
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