Math Is Fun Forum
You are not logged in.
- Topics: Active | Unanswered
#351 Re: Help Me ! » I was doing alg 2 hw, and stumbled upon Geometry problem Help please » 2005-08-16 16:00:21
I'm not sure I understand what the problem wants you to do. I'm guessing that they just want you to plug the diameter of the circle pictured into the formula they give you and write that down.
So, you need the diameter of the circle, but I have no idea what the (y+5) is supposed to represent.
Can you elaborate?
P.S.
That's an algebra II problem? Huh?
#352 Re: Help Me ! » percent difference between 2 zero values » 2005-08-16 13:22:04
I like it like this:
percentDiff = ( (A == 0) || (B - A == 0) ? 0 : ((B - A) / A) * 100) )
But everone has their own style. 
#353 Re: Help Me ! » doubling » 2005-08-16 13:15:07
To get the number x doubled n times, use x * 2^n .
#354 Re: Dark Discussions at Cafe Infinity » Music; what's your song? » 2005-08-16 12:33:59
Favorite Rock Band: Rush
Favorite Ska Band: Five Iron Frenzy
Favorite Jazz/Swing Band: The Squirrel Nut Zippers
Best Contemporary Christian CD: "Jars of Clay", by Jars of Clay (their later CD's weren't very good)
Favorite Choir: Mormon Tabernacle Choir
Best "unclassifiable": Béla Flek.
Best New Age: Adiemus
Best Guitar God: Joe Satriani
Best Undiscovered Gem: Rated Hero (look them up on Myspace and purevolume)
Runners up to the previous: Hourglass, Allred, Orion's Room
CD's I want to buy, but am too poor: Roper, "Beyond the Desert" by Dave Beegle, the new Better than Ezra, and stuff from The Fray.
I have odd taste in music. 
#355 Re: Help Me ! » total square footage of a quonset hut » 2005-08-16 12:03:31
It looks like the Wiki's designation of the quonset as a smeicircle is incorrect--it's not limited to being a half-circle only. Otherwise, the dimensions of the original quonsets that they published would be incorrect. So, it must be a segment of a circle, and we need to find the radius of that circle.
Let's center our circle at the origin and draw two vertical lines at x=40 and x=-40 (so the distance between them is 80). We know that our circle intersects both lines, and that the "top" of the circle (where it intersects the y axis) is 24' higher than that point of intersection. Connect the points of intersection, and you have your secant line.
Now:
r = (c² + 4h²) / (8h)
Source: The Math Forum
c = 80
h = 24
r = (80² + 4*24²) / (8 * 24) = 45 1/3
Now, you need to find the area (K) of the segment, but first, you need to find the central angle (theta). The formulas from MathForum:
theta = 2 arcsin( c / [2r] )
K = r²[ theta - sin(theta) ] / 2
You can then "extrude" your segment area by multiplying by the length of your quonset.
#356 Help Me ! » Reviews needed for this thing I wrote » 2005-08-04 08:01:16
- ryos
- Replies: 1
Hello MathIsFunForum,
I'm not sure where this post belongs, which might be an indication that it doesn't belong at all. Feel free to moderate me, I won't mind. 8)
As I was memorizing the unit circle, I found a few patterns that helped me remember it, and I decided I wanted to write them down. So, I did, to cement that circle in my mind and make sure I never forget it.
Then I realized that what I wrote might be useful to other people, but I won't know for sure until I share it. Now, you all have probably memorized the unit circle long ago, but I would like to ask you to take a moment to look at this and tell me if you think it's useful.
Are the explanations clear and accurate? Are any of them unnecessary? Where does the writing need polish? And, any other comments you would like to make are much appreciated.
It's a ~1 meg PDF file. (Not that it's long, it just has a few images.)
Thanks!
#357 Re: Dark Discussions at Cafe Infinity » Dont bother visiting because it's really boring in here » 2005-08-04 07:34:31
Except that when it is used as "if", it has no accent. Kinda like este, éste, and esté are three completely different words.