Math Is Fun Forum
  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

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#2 Re: Maths Is Fun - Suggestions and Comments » Mix Slider » 2009-11-26 12:14:23

This is good. The numbers above the slider are a little hard to read (over the input boxes) if it is moved far left or right.

#3 Re: Help Me ! » ln(x) = ? » 2009-08-29 20:18:35

ln(x) means the "natural logarithm of x" and can also be represented as log[sub]e[/sub](x). The natural logarithm of a number x is the power to which e would have to be raised to equal x.

However, normally to find a solution to something you first need an equation (something with an equals sign), like ln(x) = 0 or ln(4x) = 2.

Perhaps in you could try looking here:

http://www.mathsisfun.com/algebra/logarithms.html

If all that makes sense scroll down to 'Natural Logarithms: Base "e"'

#4 Re: Maths Is Fun - Suggestions and Comments » Pouring Liquid » 2009-07-08 22:26:27

Okay, tried a second time. I think I preferred my score the first time I played!

Things are well but busy, which I guess it good. How are things here? I just signed up to Mathopolis (thought I had already signed up but it turns out not). Nice work Rod, it's good fun. But my goodness, slow down mathsy, are you a bot? big_smile

#5 Re: Maths Is Fun - Suggestions and Comments » Pouring Liquid » 2009-07-06 00:00:29

I got 79 but had no cones, only cylinders. Was I playing the same game as you guys? tongue

#6 Re: Puzzles and Games » Where Are The Cows? » 2009-04-08 14:25:38

Oh no, I'm gonna be at this all day now. smile

An online version adapted from the same maze:
http://scullucs.com/wac/cows.html

#7 Re: Maths Is Fun - Suggestions and Comments » Mathopolis » 2008-11-29 12:02:05

I'm most likely doing something wrong, but I when I click 'Join' I get a fatal error ...

Fatal error: Cannot redeclare ...

#8 Re: Maths Is Fun - Suggestions and Comments » The Seasons » 2008-11-29 11:56:13

These new pages are great. Thumbs up!

I can't understand this sentence, perhaps one or two words are missing?

'It is nice to love every season, because each one has a special feeling which he would miss it was not there.'

Also, it may read easier if a 'The time' or 'The date' is added to the start of this sentence:

"when each season begins and ends is not the same everywhere!"

#9 Re: Help Me ! » Solving a Quadratic-Quadratic System by Substitution » 2008-10-25 11:35:18

If you think of this problem visually, you are trying to find the points on a graph where a hyperbola and a circle intersect.

1 -- (x+5)² +(y+2)²=169
2 -- xy - 21=0

xy - 21 = 0
xy = 21
y = 21/x

substitute y = 21/x into equation 1:
(x+5)² +(21/x+2)²=169

and expand:
x² + 10x + 25 + 441/(x²) + 84/x + 4 = 169

which gives:
x^4 + 10x³ - 140x² + 84x + 441 = 0
(x - 7)(x³ + 17x² - 21x - 63) = 0

solve for x:
∴ x ≈ -17.9734 or x ≈ -1.44775 or x ≈ 2.42112 or x = 7

#10 Re: Help Me ! » lines and angles.... » 2008-10-25 11:22:38

Using your given angle (which we can represent as t) and your given distance (we can represent as r),

r * cos(t) = x co-ordinate
r * sin(t) = y co-ordinate.

Then add the corresponding x and y co-ordinates of the two points (starting point and the point you just found).

#11 Re: Help Me ! » 6th Grade math » 2008-05-20 23:43:00

Arnie gets 50 yards, and Susan 25.



16 yards * 5 students = 75 yards

75 yards = arnie + susan, and
arnie = 2 x susan

so,
75 = 3 x susan
susan = 25 yards

75 - 25 = arnie = 50 yards.

edit - oh, good point. i can't multiply./

#16 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-27 15:13:38

Yeah yeah he has feet Zach. And good call. I was actually quite tempted to choose someone without feet just for you ...

But nah.

#17 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-26 15:32:12

1. Man, alive.
2. No, he's not a sportsperson.
3. No, he's not a cinema/television star.
4. No, he's not a politician.
5. Yes, his family name does start with a letter between A-L.
6. Yes, he was born before 1970.
7. Yes, he hails from the A continents.
8. No, he is not Asian.
9. No, he is not a writer*.
10. No, his family name does not start with a letter between A-G.
11. No, he is not a doctor.
12. No, he is not a scientist/mathematician.
13. Yes, from USA.
14. No, not a painter.
      No, not Australian ... [we can omit this]
15. Yes, a musician.
16. No, not Brodie Foster Hubbard.

#18 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-24 18:23:47

1. Man, alive.
2. No, he's not a sportsperson.
3. No, he's not a cinema/television star.
4. No, he's not a politician.
5. Yes, his family name does start with a letter between A-L.
6. Yes, he was born before 1970.
7. Yes, he hails from the A continents.
8. No, he is not Asian.
9. No, he is not a writer*.
10. No, his family name does not start with a letter between A-G.
11. No, he is not a doctor.
12. No, he is not a scientist/mathematician.
13. Yes, from USA.
14. No, not a painter.
      No, not Australian ... [we can omit this]
15. Yes, a musician.

#19 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-24 10:09:06

1. Man, alive.
2. No, he's not a sportsperson.
3. No, he's not a cinema/television star.
4. No, he's not a politician.
5. Yes, his family name does start with a letter between A-L.
6. Yes, he was born before 1970.
7. Yes, he hails from the A continents.
8. No, he is not Asian.
9. No, he is not a writer*.
10. No, his family name does not start with a letter between A-G.
11. No, he is not a doctor.
12. No, he is not a scientist/mathematician.
13. Yes, from USA.
14.  No, not a painter.
15. No, not Australian ...

#20 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-23 21:00:19

1. Man, alive.
2. No, he's not a sportsperson.
3. No, he's not a cinema/television star.
4. No, he's not a politician.
5. Yes, his family name does start with a letter between A-L.
6. Yes, he was born before 1970.
7. Yes, he hails from the A continents.
8. No, he is not Asian.
9. No, he is not a writer*.
10. No, his family name does not start with a letter between A-G.
11. No, he is not a doctor.
12. No, he is not a scientist/mathematician.

* [of words] wink

#21 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-22 19:30:29

1. Man, alive.
2. No, he's not a sportsperson.
3. No, he's not a cinema/television star.
4. No, he's not a politician.
5. Yes, his family name does start with a letter between A-L.
6. Yes, he was born before 1970.
7. Yes, he hails from the A continents.
8. Um ... I don't actually know. Hang on, I'll see if I can find out.

#22 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-19 21:28:22

1. Man, alive.
2. No, he's not a sportsperson.
3. No, he's not a cinema/television star.

#23 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-19 19:19:35

1. Man, alive.
2. No, he's not a sportsperson.

#25 Re: Dark Discussions at Cafe Infinity » Q20 » 2008-01-18 20:54:44

Play against a computer ...
http://www.20q.net/

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