## Search found 270 matches

- Sun Oct 02, 2011 11:49 pm UTC
- Forum: Mathematics
- Topic: Should we make students memorize the quadratic formula?
- Replies:
**61** - Views:
**9046**

### Re: Should we make students memorize the quadratic formula?

I think it's a bit much to make students memorize it. Just have it written at the beginning of every test for reference. It's a quick Google to find it, if they should ever need it later in life.

- Sun Aug 14, 2011 1:42 am UTC
- Forum: Mathematics
- Topic: Minecraft Shorelines are loops?
- Replies:
**18** - Views:
**3116**

### Re: Minecraft Shorelines are loops?

1.

Unless you include the possibility that some seed will generate intersecting lakes in a long chain and continues to do so indefinitely after each new chunk is generated. Does such a seed exist? Doubt it. So I'd go with 1.

Unless you include the possibility that some seed will generate intersecting lakes in a long chain and continues to do so indefinitely after each new chunk is generated. Does such a seed exist? Doubt it. So I'd go with 1.

- Sat May 28, 2011 1:49 am UTC
- Forum: Mathematics
- Topic: ∞ X 0 = -1?
- Replies:
**19** - Views:
**2551**

### Re: ∞ X 0 = -1?

In my math class (8th grade) we're learning about geometry and slopes, it is my understanding that a perfectly vertical line has a slope of 1/0 (∞ or undefined) and a perfectly horizontal line perpendicular to the vertical line has a slope of 0. We also learned that the product of the slopes of 2 p...

- Sun Apr 03, 2011 10:45 pm UTC
- Forum: Mathematics
- Topic: What is your favorite proof?
- Replies:
**41** - Views:
**5600**

### Re: What is y'all's favorite proof?

My favorite is definitely using differential equation to prove Euler's Formula. If f(x) = e^(ix), then f'(x) = i*e^(ix) = i*f(x). If f(x) = cos(x) + isin(x), then f'(x) = -sin(x) + icos(x) = i*f(x). So these both are solutions to the differential equation y' - iy = 0, and they both satisfy f(0) = 1...

- Wed Mar 30, 2011 11:32 pm UTC
- Forum: General
- Topic: Word filter reverseengineerapalooza
- Replies:
**172** - Views:
**18303**

### Re: Word filter reverseengineerapalooza

I was trying to read a few threads in the math forum but the filters were too much for me. Curse you mods.

- Sun Mar 27, 2011 8:03 pm UTC
- Forum: Mathematics
- Topic: How do I evaluate this infinite summation?
- Replies:
**13** - Views:
**2386**

### Re: How do I evaluate this infinite summation?

greengiant wrote:Try the free e-book generatingfunctionology by Herbert S. Wilf if you want to learn how to work with g.f.'s

Wow, thanks for posting this

- Fri Mar 18, 2011 4:24 am UTC
- Forum: General
- Topic: Has anyone ever called you a genius?
- Replies:
**85** - Views:
**11865**

### Re: Has anyone ever called you a genius?

The issue is that we know enough about a subject to see how much we don't know. To an outsider, we appear to know it all because they know too little about a subject to realize its scope. For example, we all thought our parents were geniuses at math when we were little because we didn't know there w...

- Mon Mar 14, 2011 10:56 pm UTC
- Forum: Language/Linguistics
- Topic: Using 'there' twice in a row
- Replies:
**19** - Views:
**3942**

### Re: Using 'there' twice in a row

"Weren't" is correct because it refers to "kids". "There" is technically the subject, but it's actually a dummy pronoun so it doesn't really mean anything without the rest of the sentence. And "there" is unmarked for either singularity or plurality. Oh that m...

- Mon Mar 14, 2011 9:44 pm UTC
- Forum: Language/Linguistics
- Topic: Using 'there' twice in a row
- Replies:
**19** - Views:
**3942**

### Re: Using 'there' twice in a row

Might be a noob question.. but wouldn't wasn't be correct rather than weren't? I can't seem to decide. What is the subject of that clause anyhoo? there? Is there plural, singular, or what?

Not to derail the thread, of course.

Not to derail the thread, of course.

- Mon Feb 21, 2011 6:45 pm UTC
- Forum: Mathematics
- Topic: Infinity and Paradoxes
- Replies:
**5** - Views:
**1383**

### Re: Infinity and Paradoxes

What you've shown is manipulation of symbols without meaning. A divergent sum doesn't actually represent a value, so how can you subtract them? Just another example of how intuition seems to fail us when dealing with infinities.

- Tue Jan 25, 2011 2:13 am UTC
- Forum: General
- Topic: Hype your ripe snipes 'n' gripes
- Replies:
**28619** - Views:
**3586313**

### Re: Rant Thread (because we need more ranting)

^ I can relate. It makes me cringe whenever someone says a variant of "I'd kill myself if ________" ... I'm not necessarily offended, and it only really hits me emotionally if I'm in a bad mood anyway, but it think it contributes to our culture's tendency to take suicide lightly. That and ...

- Sun Jan 09, 2011 2:07 pm UTC
- Forum: Mathematics
- Topic: Demonstration Graph (of dependencies on axioms)
- Replies:
**2** - Views:
**574**

### Re: Demonstration Graph (of dependencies on axioms)

You're not supposed to post a link until you have 5 posts. I'll confirm that the link is legit though. I recommend the text version.

- Fri Jan 07, 2011 9:17 pm UTC
- Forum: General
- Topic: resetting my sleep schedule
- Replies:
**13** - Views:
**2331**

### Re: resetting my sleep schedule

mstjarna wrote:This has made life worth living.

5 AM will always come too early.

This is a good suggestion. GNC sells it. Take it at the time of day that you'd like to feel sleepy and your internal clock will conform after a few days. Then you won't need it until you fuck up your schedule again

- Fri Jan 07, 2011 12:40 am UTC
- Forum: Mathematics
- Topic: Example of a student learning*
- Replies:
**15** - Views:
**2425**

### Re: Example of a student learning*

I never understood why \(\frac{(\sqrt{3}+1)^2}{2}\) was preferable to \(\frac{\sqrt{3}+1}{\sqrt{3}-1}\). Sure, it can sometimes be easier to deal with (like when performing a mental estimation) but often it is just wasted effort to convert from one to the other. I prefer rationalized denominators b...

- Thu Jan 06, 2011 10:36 pm UTC
- Forum: Mathematics
- Topic: Example of a student learning*
- Replies:
**15** - Views:
**2425**

### Re: Example of a student learning*

You didn't require them to rationalize the denominator?

- Wed Jan 05, 2011 10:23 pm UTC
- Forum: Mathematics
- Topic: "Filling in" a function
- Replies:
**8** - Views:
**1688**

### Re: "Filling in" a function

There are plenty of functions that satisfy f(x+1) = f(x) + x + 1. You'll have to give another property that will define a unique function. For example, Gamma is the unique function that satisfies f(x+1)=xf(x), f(1)=1, and log convexity. Those properties together only belong to the Gamma function. Yo...

- Mon Jan 03, 2011 2:11 am UTC
- Forum: General
- Topic: Hype your ripe snipes 'n' gripes
- Replies:
**28619** - Views:
**3586313**

### Re: Rant Thread (because we need more ranting)

I hate how our culture trivializes ADHD. It's fucking serious business, and it does exist.

- Sat Jan 01, 2011 10:58 pm UTC
- Forum: Mathematics
- Topic: A little conundrum with infinity
- Replies:
**9** - Views:
**1697**

### Re: A little conundrum with infinity

Hmm..

Well, the blue part takes up a whopping 0% of the plane, so I'd say the chances are 0 for blue.

Well, the blue part takes up a whopping 0% of the plane, so I'd say the chances are 0 for blue.

- Wed Dec 29, 2010 10:18 pm UTC
- Forum: Mathematics
- Topic: The Interesting Parts of Maths
- Replies:
**13** - Views:
**2915**

### Re: The Interesting Parts of Maths

Fractal geometry, maybe?

- Wed Dec 29, 2010 4:13 pm UTC
- Forum: Mathematics
- Topic: Proof for intergral dx/x=lnx?
- Replies:
**12** - Views:
**7888**

### Re: Proof for intergral dx/x=lnx?

Ah, continuity, I knew I was forgetting something. I'll try my hand at proving that that's enough

- Wed Dec 29, 2010 6:28 am UTC
- Forum: Mathematics
- Topic: Proof for intergral dx/x=lnx?
- Replies:
**12** - Views:
**7888**

### Re: Proof for intergral dx/x=lnx?

I have a question. Does anyone have a proof that f(xy) = f(x) + f(y), f(e) = 1, defines a unique function for positive, real x and y, provided that it truly does? In that case, I would think that to be the most efficient definition of ln.

- Fri Dec 24, 2010 6:37 pm UTC
- Forum: Mathematics
- Topic: Could someone explain this to me? (continuous function)
- Replies:
**26** - Views:
**3053**

### Re: Could someone explain this to me? (continuous function)

There is no choice of c which makes the function smooth anyways. That's true, c=0 only earns it once-differentiability at x=0. Right? (I'm fairly new to the more rigorous aspects of calculus, I'm just taking it this year at school. Edit: In fact, I shouldn't have even been trying to answer this que...

- Thu Dec 23, 2010 4:24 pm UTC
- Forum: Mathematics
- Topic: Could someone explain this to me? (continuous function)
- Replies:
**26** - Views:
**3053**

### Re: Could someone explain this to me? (continuous function)

Nope, still missed the reference. :) And that line was addressed to you. The rest was more ... vaguely frustratingly aimed. Oops, looks like I caused a mess. Yesterday I read "continuous" as "smooth" and wrote "smooth" as "continuous". Suffice to say it was n...

- Wed Dec 22, 2010 4:46 pm UTC
- Forum: Mathematics
- Topic: Could someone explain this to me? (continuous function)
- Replies:
**26** - Views:
**3053**

### Re: Could someone explain this to me? (continuous function)

EDIT: See above post. OP, ignore this discussion.

- Wed Dec 22, 2010 3:30 pm UTC
- Forum: Mathematics
- Topic: Could someone explain this to me? (continuous function)
- Replies:
**26** - Views:
**3053**

### Re: Could someone explain this to me? (continuous function)

EDIT: Nevermind, I was waaay confused about the question. Too early in the morning to be reading math.

- Tue Dec 21, 2010 6:46 pm UTC
- Forum: Mathematics
- Topic: Strange Calculus Question
- Replies:
**8** - Views:
**1196**

### Re: Strange Calculus Question

Interesting, thanks for the responses.

- Tue Dec 21, 2010 4:29 am UTC
- Forum: Music
- Topic: Places to learn Music Theory
- Replies:
**22** - Views:
**4517**

### Re: Places to learn Music Theory

In Jazz, mode means something way different, but unfortunately the names are all the same so it's hard to tell who's talking about what . It leads to heaps of confusion in the guitar world alone.

- Mon Dec 20, 2010 12:40 am UTC
- Forum: Mathematics
- Topic: Strange Calculus Question
- Replies:
**8** - Views:
**1196**

### Re: Strange Calculus Question

This is question I've been curious about for ages. If h can be defined in terms of f and g, sweet.

- Sun Dec 19, 2010 9:07 pm UTC
- Forum: Mathematics
- Topic: Strange Calculus Question
- Replies:
**8** - Views:
**1196**

### Strange Calculus Question

I have no idea how to search this. Let's say I have two continuous functions on (0, c), f(t, x) and g(t, x), for which the following have no known closed forms: \int_{0}^{c}f(t,x)dt \int_{0}^{c}g(t,x)dt If I write this: \int_{0}^{c}f(t,x)dt\int_{0}^{c}g(t,x)dt = \int_...

- Sun Dec 19, 2010 3:00 am UTC
- Forum: Mathematics
- Topic: ln(x) or log(x)?
- Replies:
**63** - Views:
**9394**

### Re: ln(x) or log(x)?

I alternate between them.

- Wed Dec 15, 2010 1:49 pm UTC
- Forum: Mathematics
- Topic: Useless Math
- Replies:
**60** - Views:
**10375**

### Re: Useless Math

Exactly. This is a philosophical question that happens to be about math. The search for an example is a part of a larger attack on the ontology of mathematical objects (numbers, sets, shapes etc.). What I'm trying to say is that they they (inclusive of irrational and complex numbers just the same a...

- Mon Dec 13, 2010 11:08 pm UTC
- Forum: Music
- Topic: Places to learn Music Theory
- Replies:
**22** - Views:
**4517**

### Re: Places to learn Music Theory

Yeah, Wikipedia isn't a very good source in this case.

Oh, and don't get caught up with modes. Just worry about tonality.

Oh, and don't get caught up with modes. Just worry about tonality.

- Sun Dec 12, 2010 6:57 pm UTC
- Forum: Music
- Topic: Places to learn Music Theory
- Replies:
**22** - Views:
**4517**

### Re: Places to learn Music Theory

I always recommend the site musictheory.net .

- Sun Dec 12, 2010 2:23 am UTC
- Forum: Mathematics
- Topic: Favorite math jokes
- Replies:
**1452** - Views:
**494828**

### Re: Favorite math jokes

Hopefully not a repost: The Flood is over and the ark has landed. Noah lets all the animals out and says, "Go forth and multiply." A few months later, Noah decides to take a stroll and see how the animals are doing. Everywhere he looks he finds baby animals. Everyone is doing fine except f...

- Fri Dec 10, 2010 10:24 pm UTC
- Forum: Language/Linguistics
- Topic: Do you use the term "Ginger"?
- Replies:
**65** - Views:
**20609**

### Re: Do you use the term "Ginger"?

Where I'm from, "ginger" is used to describe someone with red/orange hair, pale skin, and light brown/orange freckles.

- Thu Dec 09, 2010 12:51 am UTC
- Forum: General
- Topic: Hifaleetin' thoughts
- Replies:
**90225** - Views:
**9391670**

### Re: Momentary/Meandering/Meditations (Random like the plague

Do Hindus generally find "holy cow!" to be offensive?

- Mon Dec 06, 2010 1:44 am UTC
- Forum: Mathematics
- Topic: Useless Math
- Replies:
**60** - Views:
**10375**

### Re: Useless Math

Fractals were once believed to have no practical application, I think.

- Sun Dec 05, 2010 11:04 pm UTC
- Forum: Mathematics
- Topic: Forming a proof about a triangle
- Replies:
**10** - Views:
**1713**

### Re: Forming a proof about a triangle

Um... no. You've just proved the converse . The converse does not imply the original problem. What would be an equivalent thing to show is the contrapositive, which in this case would be to show that if a right triangle is not isosceles, then its area is not z^2/4. Right, right. But I thought it wa...

- Sun Dec 05, 2010 6:11 pm UTC
- Forum: Mathematics
- Topic: Forming a proof about a triangle
- Replies:
**10** - Views:
**1713**

### Re: Forming a proof about a triangle

You reached this result in a really roundabout way. Start with the formula for area: A=(xy)/2 Using the assumption that x=y: A=(x^2)/2 But, using that same assumption on the Pythagorean Theorem: z^2 = x^2 + y^2 z^2 = 2x^2 (z^2)/2 = x^2 So by substitution: A = ((z^2)/2)/2 Simplify and you have your r...

- Sat Dec 04, 2010 11:10 pm UTC
- Forum: Mathematics
- Topic: Would this be a proof?
- Replies:
**14** - Views:
**1806**

### Re: Would this be a proof?

Next step: prove that there is an infinite amount of coprime Pythagorean triples...

Edit: By the way, I agree with the post below me. The way you wrote it was neither concise nor particularly clear. But the idea was definitely there.

Edit: By the way, I agree with the post below me. The way you wrote it was neither concise nor particularly clear. But the idea was definitely there.