Science & Mathematics - 29 November 2007

How are they different from other valves ?

2007-11-29 23:38:55 · 1 answers · asked by robin 3 in Engineering

they told me Algebra.. and something called linear algebra.. i really dont remember :( so what should i learn 1st


ps - ive ordered a book from amazon! (Calculus by Spivak)

2007-11-29 23:35:30 · 8 answers · asked by ? 4 in Mathematics

What if farther into the Milky Way Galaxy, there was a huge star, far greater than the sun's mass, and it pull everything in the Milky Way towards it, and made them orbit. What if the sun was a planet orbiting that huge sun, and the planets were the moons of the sun? Would this ever be feasible? But since the huge star is so far away the sun doesn't seem to move. Do stars move by gravity? If so I think this could be a plausible idea. Please if im totally wrong and nothing makes sense keep the critizism to a minimum.

2007-11-29 23:21:46 · 16 answers · asked by Anonymous in Astronomy & Space

2007-11-29 23:04:53 · 8 answers · asked by 01101001 3 in Mathematics

to increase fuel economy by assisting acceleration?

2007-11-29 22:56:49 · 6 answers · asked by pete the pirate 5 in Engineering

well i went to sleep at 3 and at 3:15 i cud smell cigarette smoke..i thought it was my roommate so i opened ma eyes but saw that he too was fast asleep on the bed next to mine..i trie to wake him up but cud not move a single inch from ma bed nor could i speak anything...i felt something hard pressing on me I stayed in this state for abt 15 mins and suddenly everything became normal

2007-11-29 22:48:15 · 20 answers · asked by ANDY 1 in Paranormal Phenomena

2007-11-29 22:37:25 · 16 answers · asked by Anonymous in Mathematics

may someone please explain step by step. im a newbie and im lost....

thanks

2007-11-29 22:35:58 · 3 answers · asked by * blobbaah- 1 in Mathematics

2007-11-29 22:26:02 · 4 answers · asked by ruhail774 2 in Biology

Hi
I am a Physics student and recently read about Bose-Einstein condensation. A couple of questions came to me that you might be able to answer.
1. If an object approaches absolute zero will it gradualy start to disappear due to the fat that there will be a reduced number of photon emisions due to reduced transitions to different energy levels.
2. Does an object have a reduced or no mass at or approaching absolute zero. Does this mean that hotter objects have greater mass than cold objects.

Answers to these questions would be much appreciated.

Many thanks

dba

2007-11-29 22:12:08 · 4 answers · asked by Anonymous in Physics

This is quite embarassing... I do the highest level of maths available in high school yet..

basic 3-unit trigonometry eludes me at the moment.

Remind me again how to solve cos2x = x for x?
And yes, I can do it, but I need to know the proper method to be able to solve harder ones coming up in the test.

I suppose this shows that no matter how easy the maths is, if you can't remember it.. it's very challenging..

(General solution is needed.)

2007-11-29 22:08:33 · 7 answers · asked by Girl 5 in Mathematics

2007-11-29 21:55:40 · 47 answers · asked by Anonymous in Geography

2007-11-29 21:53:28 · 13 answers · asked by Anonymous in Earth Sciences & Geology

What do people learn in university about math? (heard that there is less manipulation of numbers and more proving)
What is the most interesting topic to you and why?
What is the most challenging topic to you and why?

2007-11-29 21:44:59 · 5 answers · asked by Anonymous in Mathematics

Crackpots or weirdo's.

2007-11-29 21:42:56 · 16 answers · asked by Anonymous in Paranormal Phenomena

A middle-aged woman comes to the clinic complaining of stiff, painful joints and increasing immobility of her finger joints. A glance at her hand reveals knobby, deformed knuckles. What condition will be tested for?

2007-11-29 21:42:03 · 8 answers · asked by clicked 1 in Medicine

2007-11-29 21:32:24 · 3 answers · asked by me 1 in Weather

Could noncoherent detection be used with PSK signals?
thats all thanks

2007-11-29 21:32:14 · 1 answers · asked by mascix 2 in Mathematics

Please don't quote chicken and egg. Please don't explain how some animals are both male and female, All that is elementary bioligy. The question is, What happened to make the first gene split into the different sexes? The man/woman question is irrrelevant. Is it possible that M/W developed from differant species?

2007-11-29 21:25:15 · 29 answers · asked by Anonymous in Biology

Prove that the decimal expression of any rational number is periodic. For this, let a/b be your rational number, with (a, b) = 1 and b belongs to N.
(a) Show that there are two different non-negative integers k > l >= 0 such that (10^k − 10^l) is a multiple of b. Hint: if (b, 10) = 1 then apply Euler’s theorem. If not, write b = b1 x b2 with (10, b1) = 1 and b2 = 2r1 x 5r2 . Apply Fermat’s little theorem to b1 and figure out what to do with b2.
(b) Say why the previous part implies periodicity of the decimal expression. What can you say about the period?
(c) The decimal expression is said to be pure periodic if the periodic part starts “right after the dot”. For example, 43/6 = 7.16, 1/56 = 017857142 and 2/15 = 0.06 are not pure, while 10/11 = 0.90 and 1/37 = 0.027 are pure. Show that the decimal expression of a/b is pure if and only if (10, b) = 1

2007-11-29 21:17:07 · 2 answers · asked by azn137 1 in Mathematics

A trapezium is divided into 4 triangles by its diagonals. Prove the ares of the coloured triangles are equal. Thank you

Try to imagine that the coloured triangles are the left and right triangled in the trapezium, meeting vertically opposite, instead of the ones above and below

2007-11-29 20:49:49 · 3 answers · asked by little zebulon 4 in Mathematics

2007-11-29 20:23:33 · 28 answers · asked by . 1 in Mathematics

2007-11-29 20:16:13 · 4 answers · asked by Miss Zippy 2 in Chemistry

I am offered a new technology Electrode earthing, where-in they use a 3mt G.I. electrode and fill the pit with a compound, mainly containing 'Sodium-bentonite', which is supposed to retain moisture 13 times it's volume and for quite long so that frequent watering is not required. But the initial ohmic-value of the earth point is not guaranteed, because they say the ohmic-value depends on the soil resistance.
But conventional plate earthing guy is saying you will definitely get even less than 1 ohm resistance also. But problem here is that the plate will start corroding in 3/4 years, due to presence of heavy salt and thus resistance will automatically increase then.
But in Electrode earthing, whatever is the initial resistance, it remains the same for many years as there is virtually no corrosion at all because the compound has a neutral pH value.

My question is, is it OK to mix bit of salt in the compound, so as to get the initial ohmic-value very low ?WHICH IS BETTER EARTHING ?

2007-11-29 20:07:45 · 5 answers · asked by Anonymous in Engineering

solve the system.
xsqaured +ysquared =16
x+y=1
what are the solutions for x and y

2007-11-29 19:55:56 · 6 answers · asked by Purple 2 in Mathematics

2007-11-29 19:48:05 · 9 answers · asked by ashu 1 in Geography

I need some help on this problem for Calc 1. I can't get the right numbers to come out.

I know how to find max / mins , and inc/dec , but this problem is harder than others and i need someone to show me how to do it.



a. Find the intervals on which f is increasing or decreasing
b. Find the l0cal maximum and minimum values of f.
c. Find the intervals of concavity and the inflection points

f(x) = (e^x) / (1 + e^x)

need to get crit numbers first and derivatives

Thx

2007-11-29 19:45:14 · 2 answers · asked by brobo8 1 in Mathematics

2007-11-29 19:41:14 · 3 answers · asked by Anonymous in Biology

I think log (10) 2 is 2/5 because at first 2 is over the sq root of 10 then you power up the 2 to make 4 then square root it so that the entire things a fraction but then hm.. I messed up.

2007-11-29 19:40:54 · 4 answers · asked by Anonymous in Mathematics

How do you find what the PST and GST tax was if they only give you the tax %s and the price including taxes.

ex. GST=7%, PST=9%
price including taxes is + $19.99

7%+9%=16% TAX

19.99/1.16 (total tax) =17.23 is the price before tax.
so 19.99-17.23=2.76 this is the total amount of tax 7% and 8%.

Now how do I find out what the GST and the PST of the total tax price 2.76 are.

2007-11-29 19:30:31 · 5 answers · asked by Anonymous in Mathematics