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Topic review (newest first)
- flagitious-t
- 2005-07-24 08:39:45
uhh... both?
- Zach
- 2005-07-24 08:23:17
Cookies. They're really complex.
- MathsIsFun
- 2005-07-24 08:01:15
flagitious-t wrote:
wow, really complicated.
Titanic or the Cookies?
- flagitious-t
- 2005-07-24 03:57:14
thanks!
wow, really complicated.
- ganesh
- 2005-07-23 20:29:02
Thanks, Mathsisfun,
I am on the verge of post # 200
and this an occassion for me to celebrate,
I shall take a big chunk of thhat 
- MathsIsFun
- 2005-07-23 20:21:34
These look particularly yummy.
Mathsy gets first choice.
- ganesh
- 2005-07-23 19:58:25
My head is reeling 
- mathsyperson
- 2005-07-23 19:39:24
My fault again! "Haha!"
I got the sectors the wrong way around.
Length x sector's angle: cos-¹(1-x²/1800)
Length 30 sector's angle: cos-¹(x/60)
So, the latest formula is =900*PI()*ACOS(1-B8*B8/1800)/(2*PI())+B8*B8*PI()*ACOS(B8/60)/(2*PI())-SQRT((30+B8/2)*(B8/2)*(B8/2)*(30-B8/2))
Edit: And it works perfectly! Cookies for everyone!
To the nearest cm, the goat's leash is 34.76m long.
- MathsIsFun
- 2005-07-23 19:14:34
Oh, rats ... I mean goats. Well, the answer is somewhere in there. Maybe flagitious can take it from here.
- mathsyperson
- 2005-07-23 19:03:54
We still haven't cracked it though. When the goat's leash has length 0m, it can apparantly eat around 700m² of grass. It must have a long neck...
- MathsIsFun
- 2005-07-23 18:51:09
See? My turn to be foolish. I have already had my flash of brilliance for today - it is all downhill now 
- mathsyperson
- 2005-07-23 18:34:10
And then it would just be strange: "Math Is Forum"
All I can see is that you haven't divided the sector areas by the number of whatever you're measuring by. Excel works with radians by default so try this:
=900*PI()*ACOS(B8/60)/(2*pi()) + B8*B8*PI() *ACOS(1-B8*B8/1800)/(2*pi()) - SQRT((30+B8/2) * (B8/2)* (B8/2) * (30-B8/2))
- MathsIsFun
- 2005-07-23 18:20:02
"Sorry"? Try "Haha"!
( Gee, if we all have to be worried about making mistakes then we may as well take the "Fun" off the forum name. )
Still not quite there ... maybe i am not getting my formula right.
=900*PI()*ACOS(B8/60) + B8*B8*PI() *ACOS(1-B8*B8/1800) - SQRT((30+B8/2) * (B8/2)* (B8/2) * (30-B8/2))
If you have a chance, see if you can get it working, then just delete the last two or three posts and show the world how neat and perfect we are!
- mathsyperson
- 2005-07-23 18:05:14
Sorry, I've given you a duff formula. The two sectors 'areas' are actually just their angles. *Feels stupid*
The real area: 900Π*cos-¹(x/60)/360 + x²Π*cos-¹(1-x²/1800)/360 - √((30+x/2)(x/2)²(30-x/2))
Sorry again!
- MathsIsFun
- 2005-07-23 18:00:54
ACOS() ?
Pi is there, it just looks weird: Π
By the way, I tried that formula in excel with "30" for x and got -387.617, have we somehow created anti-grass?
Formula: =ACOS(B8/60) + ACOS(1-B8*B8/1800) - SQRT((30+B8/2) * (B8/2)* (B8/2) * (30-B8/2))