# Willa

Members

27

1. ## The mind's eye

Just found out this has a name. http://en.wikipedia.org/wiki/Tetris_effect
2. ## How to calculate the probability of hair colour of a child

At least at my middle/high school, we did Punnett squares a lot: http://en.wikipedia.org/wiki/Punnett_square Definition an oversimplification for complex traits like height and hair color, but it's a start.

6. ## The mind's eye

Same thing happens to me with Tetris. If I play it for too long, I start seeing falling blocks and can semi-play the game in my head.
7. ## The Official "Introduce Yourself" Thread

So I apparently had an account here four years ago (needless to say, I had forgotten all my login info), but I completely forgot about this site until a couple days ago. I figured I'd stop by again and get my fill of CS/math/puzzles/scientific news About myself: I like dancing, cartooning, and computer programming. Oh and long walks on the beach.
8. ## Daedalus' Fifth Challenge

I haven't done calculus in a long time, so I hope I don't do anything silly...

10. ## Deleting Objects in Java

I just uncovered this post of mine from forever ago, when I was starting to learn programming. 4 years and many real CS courses later, I have no idea what this question means. xD

You so totally Did not credit the author. Perhaps I'll sue you.
12. ## Can pi be reduced to a rational number?

I do realize the sophistry involved in my argument...I was just betting on my opponents not being able to pick it out.
13. ## Of Biology, Physics and Chemistry which one did you find to be the hardest/easiest?

Luckily for you, I have a high-quality photograph of all three of them together! Group Photo
14. ## Can pi be reduced to a rational number?

Hehe...this reminds me of the first debate of my Debate class last semester. The topic was "Is pi better than pie?", and I argued the pro-pie side. Basically I argued that because perfect circles do not exist in real life, pi does not exist, and therefore cannot be better than anything. Hey, we won. -- Part of our opening case: Contention #1 a. Examples of mathematical concepts that do not actually exist – only approximations i. Square ii. Circle iii. Pi b. No such thing as a perfect mathematical circle i. Irregularities ii. On computer: collection of square pixels iii. Borderline has thickness c. Pi based on nonexistent circle i. Ratio of circumference to diameter ii. Pi itself does not exist iii. Cannot be better than pie, which does exist iv. Cannot be better than anything -- Of course, I conveniently forgot to mention that mathematical concepts that do not represent the tangible world precisely can still be highly useful, and that most of our technology would fall apart without them.
15. ## Of Biology, Physics and Chemistry which one did you find to be the hardest/easiest?

From cutest to least cute: Biology, Physics, Chemistry
16. ## Humans as Omnivores

Umm, I think I watched a documentary that said that, before humans ate meat, we scavenged bone marrow from dead animals. (Hm, would bone marrow be considered a form of meat? Maybe. It doesn't fit in any other nutritional group.)
17. ## Can pi be reduced to a rational number?

The side length of a square may very well an irrational number too... then the area of that square might be irrational. At the same time there are circles with rational areas--say the radius is $\frac{3}{\sqrt{\pi}}$, then the area would just be 9. So, there's no real difference between the rationality of areas of squares vs. circles. If you have a square with area 2, then the side length must be $\sqrt{2}$, which is an irrational number. Would you suggest that this should be a rational number as well?
18. ## A couple biology question I don't get.

The first question sounds like an example of imprinting, even though it's taking place on the mother's part (rather than the offspring's, as usual).
19. ## Circle Problem

Unless I'm grossly misinterpreting the problem, there's no need for trigonometry at all... 2 is the arc length, not the chord length, correct? After you find the angles of the triangle, you just need to use the formula for arc length (AKA application of basic circumference formula), which can be found in the link that big314mp posted. No sines or cosines anywhere.
20. ## Deleting Objects in Java

Thanks! After a little thought, I figured out how to implement the function without backtracking (although it still seems unnecessarily complicated to me). I guess all I needed was a bit of a rant...disguised as a civilized computer science question.
21. ## Math and word processor

There's always pencil and paper, too, right?
22. ## Deleting Objects in Java

It's very frustrating that objects can't be explicitly deleted in Java... I can change the reference and let garbage collection delete it, but this gets tricky when there's more than one reference to the object. Why does Java have this limitation and is there any way to get around it? Specifically, I'm trying to implement a binary search tree. Ultra-specifically, I'm trying to write the function to delete a node. Deleting a leaf should be easy--just get rid of it. But it's turning out to be the hardest type of node to delete because to "just get rid of it," I have to go back and find the parent node, figure out whether the leaf is on the left or right branch, and set either left or right to null. I'm not sure whether my instructor intends for us to simply use the built-in class java.util.TreeSet, but while I'm waiting for him to return my email... might as well learn something new, right?
23. ## Circle Problem

How can you find the length of AB...? It seems to me that B can be any arbitrary point along that line (AB).
24. ## Most Elegant Math Equations Ever

$\frac{d}{dx}[e^x] = e^x$ Even though $e$ was defined to fit this very equation, I still love the fact a simple exponential function has this property. "Who has not been amazed to learn that the function y = e^x, like a phoenix rising from its own ashes, is its own derivative?" ~ Francois le Lionnais
25. ## Correct?

That's right. In order to subtract the two fractions, you first have to find a common denominator. Since the common denominator would be 2g, that is the denominator in the answer as well.
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