Explanation Definition and 961 Threads

Homework Statement 2. On the domain x \geq 0; y \geq 0, dene the function f(x; y) such that [PLAIN]http://img100.imageshack.us/img100/2144/huhh.jpg Homework Equations I'm not so sure. The Attempt at a Solution I apologize for no attempt. I am just totally confused with this notation as I...

The equation for a circle is x = r cos(u) y = r sin(u) Where u is 0 <= u <= 2 pi, because 2 pi is for calculating circle. While a sphere is x = r cos(u)cos(v) y = r sin(v)cos(v) z = r sin(v) Where u is the same, 2 pi but v is 0<= v <= 1 pi. Why only 1 pi for v? and not 2...

Homework Statement "A rock climber throws a small first aid kid to another climber who is higher up the mountain. The initial velocity of the kit is 11 m/s at an angle of 65 degrees above the horizontal. At the instant when the kit is caught, it is traveling horizontally, so its vertical...

Homework Statement My teacher posted this solution. It is exactly what I had, except I did not have 4Pi in the numerator. Rather, I had 2 instead of 4, and I didn't have Pi. The solution manual has had mistakes before, so I am wondering if that's what the case is here. Every other step, I had...

Homework Statement theorem: There is at least 1 rational # in any interval Say a<b and let I = (a,b). Let n be a positive integer so large that 1/n < b-a and consider the numbers k/n (where K is an integer). Then there will be a K such that k/n EI I'm just having a bit of trouble...

Homework Statement A 2.0 kg mass , placed on a smooth, level table, is attached by a light string passing over a frictionless pulley to a 5.0 kg mass hanging freely over the edge of a table. Calculate... a) the tension in the string b) the acceleration of the 2.0 kg mass on the table.The answer...

I'm pretty sure this isn't a homework style question. o_O could someone please explain this, I may be overly tired, but it's confusing me: "A further illustration of this rule is generally given by algebraists as follows: First, we know that +a multiplied by +b gives the product +ab; and...

I have a BS in physics from some time ago. In another forum on another board I have become embroiled in a discussion with another poster about SR and the need to adjust the clocks on GPS satellites to account for SR effects. I need some help trying to explain things. As expressed by the other...

Homework Statement I need someone to help me fully understand Newton's Laws. I kinda get his second law, the sum of the forces equals mass times acceleration??, but yea. Homework Equations Newton's First Law Newton's Second Law...

can anyone explain that domain or give me any reference about it??

on an aeroplane, why does air fly FASTER over the top than the bottom. I get everything else; i.e: higher pressure moves to lover pressure. What I don't get is how the air flies faster over the curved part of the wing. Please explain simply thanks

UK Ministry of Defense Report Findings "The UK Ministry of Defense report "UAP in the UK Air Defence Region[2] released to the public in 2006 draws several conclusions as to the origin of "Black Triangle" UFO sightings. Their researchers conclude that "Black Triangle" UFOs are formations of...

Explaining without explanation Go into any bookshop (at least in the UK) ad under Popular Science you will find Science majorly represented by things like String Theory and then maybe Cosmology and Prime Numbers or very fundamental (particle) physics and then quantum philosophy. There is far...

Greetings, I've stumbled upon some peculiar images of our sun that appear to have extremely large objects in orbit which don't appear to be planets. The images are from the following NASA database. Each image is taken every ~10 minutes...

In the situation where differences between consecutive squares, (or consecutive cubes, consecutive x^4, etc.) are calculated, then the differences between those differences are calculated, and then the differences of those differences, and so on until you reach a constant number at a deep...

The Hill sphere of a celestial object is the area in which it is the dominating force in the area. I was wondering how the formula was determined. If the mass of the smaller body is m, and it orbits a heavier body of mass M with a semi-major axis a and an eccentricity of e, then the radius...

I am from HK. Hope you guys can understand my poor English! ^^ actually, this is not for my homework but my preparation for the public exam. Homework Statement The situation is that a ball bouncing up and down on the ground in vertical direction. The question is to choose which graphs best...

I've been trying to learn more about tensors with the help of this website, http://www.grc.nasa.gov/WWW/k-12/Numbers/Math/documents/Tensors_TM2002211716.pdf, but its explanation on one little part about vectors has me puzzled. It states that an inner product of a vector S and a dyad expressed...

Most of my friends, both on PF and in person, are accustomed to me using the phrase "balls-to-the-wall" to indicate a flat-out effort. It never occurred to me, until someone (in person) mentioned it earlier today, that it might be deemed offensive by some. I want to explain that there is no...

What is the easiest way to see that, in a regular polyhedron, the sum of the face angles about each vertex is less than 2π? This seems elementary, but I truly have very little background in geometry. Preliminary searches on PF and Google/Wikipedia didn't turn up anything substantial aside from...

Hello, My professor wants us to code a program that encrypts a massage and decrypt it , I know that to encrypt something you need a message and a key, and you assign a number to each letter or the message, and you do the same with the key, and then you add the two numbers together to get...

I got this from a book anyway An astronomer called William Herchel used some very accurate and sensitive mercury thermometer, he placed one in front of a spectrum of light and found that as he moved it across the bands of different colors from violet to red,the temperature rose. this...

Triune Brain Not rigorous enough for pure neuroscience. But rigorous enough for people to grasp the brain? The actual reality is complex and gritty. Yet we don't explain the reality of quantum physics- we present simple, understandble analogies for people to grasp. My question to...

Can anyone tell me ?how should i idetify transister type ?i simple want to know .from the board.it is pnp transister or npn transister physically.Kindly let me know the idea.Any help woud be highly appreciated.

Homework Statement The graphs show the force Fi (in pounds) required to move an object 9 feet along the x-axis. Order the force functions from the one that yields the least work to the one that yields the most work without doing any calculations. Explain your reasoning. Homework...

OK I have been stuck up with this VIP experiment relating to pauli's exclusion principle, I reached here somehow by searching about the tetraneutrons but anyways can anyone explain me waht the following lines convey ? "The VIP experiment aims to improve the current limit on the violation of...

What is impurity doping? Can somebody please explain it?

Hi, I've read several times an explanation of entropy that describes it something like "log of the number of states that are macroscopically indistinguishable". So the entropy of a system depends on the number of positions all the particles in the system can be in - right? If a system is...

There is an old weird theory that an antiparticle is actually a particle going back in time; when a pair is born "out of nowhere", it's in fact one particle making a U-turn in time. Now, consider the expanding Universe. Let's say you are observing a nearby spinning galaxy drifting away from...

Im currently in Calc II and am finding myself totally lost when it comes to solving things like sin(pi/3) and trig of that nature. I am very reliant on my calculator and am extremely fond of degrees, but I NEED to be able to find the definite integral of cos(x) from 0 to (pi/3) and problems that...

I don't need the template because this isn't a homework problem, per se; it's just information about how to get started on my homework. So I have an equation x'=Ax, x(0)=x0, where A is a constant matrix. I can write it as x=ø(t)x0, where ø(t) is a fundamental matrix such that ø(0)=I...

Can someone give me a layman’s terms explanation of what a null space is .

I'm looking for an explanation for the fountain effect in superfluids using the 'two fluid model'. However the explanations I've come across are not very satisfactory From the NASA website http://cryo.gsfc.nasa.gov/introduction/liquid_helium.html But why does superfluid Helium flow...

Hello, Your forum was very helpful in giving intuitive geometric explanations to various concepts from differential geometry, so I was hoping you could perhaps help me with the following. I'm interested in Killing vector fields. I understand that a tangent vector field X is a Killing vector...

I have cola-bottle (1.5L) that is half-filled with water. The other half was air, of course. I put it in the fridge (~ -14 C) and after about an hour, before i could see ice formation but when it was very cold nonetheless, i saw that the bottle hull was deformed to the inside, the same way if...

i think I have an alternative explanation to the double slit.We can assume that the slit surface is not completely smooth,thus a photon may enter these gaps thus allowing for interference in the case of single photon emitter

Can someone explain to me why Cv is used in this example? Determine delta S for the conversion of a monatomic ideal gas from state 1 to state 2. Cv = (3/2)R, Cp = (5/2)R State 1: V1 = 22.0L, P1 = 1.25atm, T1 = 308K, n=0.917mol State 2: V2 = 34.0L, P2 = 0.700atm, T2=325K, n=0.917mol...

The correct answer is (1/y) - (1/xy) but i don't understand why What does the sum of xy not equaling zero imply that we can do to the equation to solve it?

Take any whole number and add the digits down to a single number. Now, subtract this number from the original number. With this answer add the digits down to a single number and it will always end up being 9. Example: 22 (2+2=4) 22-4=18 (1+8=9) or 14567 (1+4+5+6+7=23 and...

Can a couple of you smart folks on here explain to me in simple terms (as simple as possible) what General Relativity and Special Relativity is? Also, if you don't mind, provide examples, if you feel it is needed for further explanation.

Can anyone provide, or point me to, an explanation of minimum ionizing radiation? My understanding is that in the limit of ultrarelativistic velocities, a charged particle stopping in matter has a dE/dx that approaches some limit. Is this correct, and if so, why does it happen? Is it basically...

explanation of word "foliation" in quantum gravity? I please for explanation of word "foliation" in quantum gravity?

How do you express impedance in terms of w(omega), R, L and C knowing the circuit diagram. I understand that for R Z=R L Z=iLw C Z=-i/wC What is the effect of having components in parallel/series, could someone please give an example of a circuit and it's impedance expression...

I want a detailed circuit with explanation on the automatic voltage regulator for synchronous generators if anyone has

Homework Statement Hi all, I've just calculated the first three nonzero terms of the Laurent series of 1/(cos(z)-1) in the region |z|<2pi, and now I've been asked to 'find the three non-zero central terms of the Laurent expansion valid for 2pi<|z|<4pi' - firstly, what does it mean by...

I teach marine biology and have been presenting the traditional model of the equilibrium tidal theory (2 humps on rotating earth) as still presented in most basic texts, but have not been able to find the theory or presumed explanation for the apparent generally increasing amplitude in tidal...

Please see here: http://www.youtube.com/watch?v=n5bsQ_YDYCI&feature=player_embedded# First - wow. Second - I'm not sure I understand the mathematician's explanation. Why would there be a thin layer of air to begin with? Is this correct? Is there a different explanation for this...

[SIZE="4"]Could anyone who knows give me a really simple yet realistic explanation of the doppler effect. This is one of those things that just boggles the brain so to speak.

I saw a contour integral in a text I was recently reading, but unfortunately a contour integral is beyond my understanding at the moment. As such, I would greatly appreciate it if someone could explain a contour integral to me. If it helps, I know about derivatives, integrals, partial...

Re: the absorption & re-emission of long-wave radiation in the Earth's atmosphere. I thought it all made sense until I was trying to work out how to explain it better to others! So the Beer-Lambert equation describes the absorption at a given wavelength as exp(-k.z) where k is a constant...