Math Is Fun Forum
You are not logged in.
- Topics: Active | Unanswered
#151 Re: Help Me ! » Circular sequence results » 2006-02-07 03:45:14
Are you doing these by hand?
#152 Re: Help Me ! » A sphere of mass » 2006-02-07 03:43:14
In my experience, physics problems such as these want you to start from basic and derived formulas that you have learned and manipulate them into the equation they want you to prove.
If we covered that part of physics in my last course, I must have missed it (I hated that class 
). So, I can't actually help you. But, maybe that will set you on the right track.
#153 Re: Introductions » I've been here about three months, but.... » 2006-02-07 03:38:58
What's more American than taxes? I am! I am! I am! (Sing it with me!)
Sorry...I suppose posting early in the morning (8:40 is early to me) is the same as late at night.
#154 Re: This is Cool » Number theory #1 » 2006-02-07 03:32:25
¡Ay chico, estás hablando Chino!
So, is (mod a+b) a modulus operation? And why bother if you multiply it by zero? And how can you define the product of two natural numbers to be zero?
What's a rom (besides a read-only memory)?
Or were you joking? 
#155 Re: This is Cool » Time may have a geometry » 2006-02-06 17:42:57
Hey Ricky, aren't neutrinos mostly massless (as in, massless as photons, or more)?
I thought that the dark matter theory was invented to explain why calculations (based on gravitic interactions) of the mass of the universe come out much larger than the observed electromagnetic luminosity of the universe. It seems to me that an excessively large amount of neutrinos would be required to make up the deficit, but I admit to a degree of ignorance here.
#156 Re: Help Me ! » Quotation and Chain Rule HELP » 2006-02-03 10:28:29
Can anyone say polynomial division?
#157 Re: Help Me ! » equation » 2006-02-03 09:33:43
As far as I can tell it can't be done algebraically. I'm guessing that this was assigned to teach the rational roots theorem? Unfortunately, I don't remember the theorem, just the name.
My calculator gives 4 roots between 0 and 1.
#158 Re: This is Cool » what is discrete math? » 2006-02-03 09:03:26
<?php
function canOpener ($can) {
$canOpened = false;
$args = func_get_args();
unset ($args[0]); //that's $can; we have that one
foreach ($args as $compareTo) {
if ($can == $compareTo) { $canOpened = true; }
}
return $canOpened;
}
?>
#159 Re: Help Me ! » Quotation and Chain Rule HELP » 2006-02-03 07:22:59
y′ = 5(2x+1 / 3x - 2)^4 * [ (3x-2)2 - (2x+1)3 ] / (3x-2)²
= 5(2x+1 / 3x - 2)^4 * -7 / (3x-2)²
#160 Re: This is Cool » what is discrete math? » 2006-02-02 11:26:30
Hmm...case true eh? Pretty slick. I had thought of the rollover switch, but it seems like using a sledgehammer to open a can. Almost easier to just use a knife. But what I really need is a can opener...
#161 Re: Help Me ! » arc length » 2006-02-02 06:53:04
I'll look at it later today. I need to study for my Calc test anyway.
#162 Re: Help Me ! » Planes Of Symmetry » 2006-02-02 06:51:19
I'm not sure I quite understand what is meant by "plane of symmetry." If it is just "a plane that passes through the object which cuts it into two symmetrical pieces," then a cube would have an infinite number of such planes. Just pass a vertical plane through the center, and rotate it by infinitesimal amounts. It will always be symmetrical, regardless of the angle!
#163 Re: This is Cool » what is discrete math? » 2006-02-02 06:08:46
OK. Too right. I still wish their were a language construct for compacting conditions wherein a variable could equal one of several things that trigger the condition.
#164 Re: Dark Discussions at Cafe Infinity » imballanced brain... » 2006-02-01 12:33:46
Ok, make that no two people are not on fire.
More seriously, when I study most things I listen to music, but when I study Math music gets in the way. Listening to lectures or other spoken-word programs gets in the way of most things, but it actually helps while doing math!
It's like I need something to occupy one half of my brain so it will get out of the way of the other half.
#165 Re: This is Cool » what is discrete math? » 2006-02-01 11:00:45
Heh, I think exactly opposite. My first programming language was C at age 13. My first OOP language was Java at age 18. Both were very easy to learn, but using Java is much easier. This is mainly due to Java's memory handling and extensive API. And after using a language that abstracts strings, I just can't bring myself to use a language that doesn't (of course, I'm sure people have abstracted strings tons of times in C++, but I doubt it's as slick as native support).
I'm starting to learn Ruby, which is supposedly nice enough to make PHP blush with shame.
#166 Re: This is Cool » what is discrete math? » 2006-02-01 10:43:01
Well, PHP. I've never written a line of C++, and hope I never have to.
#167 Re: This is Cool » what is discrete math? » 2006-02-01 10:31:13
Does boolean algebra have a distributive property?
For example, I often wish I could say: a == (b or c or d)
instead of: (a == b) or (a == c) or (a == d)
...but the first form doesn't work.
#168 Re: Dark Discussions at Cafe Infinity » imballanced brain... » 2006-02-01 10:21:55
No two people are not on fire.
#169 Re: Dark Discussions at Cafe Infinity » How to Do What You Love » 2006-01-30 13:20:16
It just looks long because the column is narrow.
This article reminds me of the time I quit school. At the time I thought I was doing it to learn more, and I certainly taught myself things no high school would, but in the end I think I traded quantity for quality.
However, the most important thing I learned through that is that learning how to do cool stuff often stinks. My major is a prime example: chemical engineering. Worst. Classes. Ever. But once you're through you have powerful knowledge, and applying it is a blast.
Why should that be so? I think it's because the work is just as difficult and exhausting as solving real problems, without the benefit of having solved real problems. But, it's rare to be able to do something real while learning how to do it. You have to practice first.
I want to solve energy problems, and I think I'll have to take the organic route to do it...
Do you do what you love? What do you do and why do you love it?
#170 Re: Dark Discussions at Cafe Infinity » Year of the Dog » 2006-01-28 16:51:59
I'm a dog. Woof!
#171 Re: Help Me ! » Recursions » 2006-01-27 19:15:25
i. I think so.
ii. It stands to reason that, although the numbers will get so small as to be essentially 0, there will always be some teeny tiny insignificant bit more to add. I wouldn't know how to find out, though.
iii. Sure there is: ƒ(x) = sin(x-1)
#172 Re: Help Me ! » anitderivative of 1/sqrt(x) » 2006-01-22 12:58:45
He was asking for the antiderivative, AKA the integral.
1/√x can be rewritten as ½x^-½. This can be integrated simply by the power rule for integration: ∫½x^-½dx = x^½ or √x.
#173 Re: This is Cool » Math *IS* Fun » 2006-01-21 18:55:41
::Rafiki voice:: Look harder...
#174 Re: This is Cool » Math *IS* Fun » 2006-01-21 14:57:38
v1.1. TROZ!
#175 Re: This is Cool » Math *IS* Fun » 2006-01-20 21:05:11
Thanks, guys! I'll see if I can improve it now - my computer has decided to rebel against me. Launching Illustrator might just do it in...