Exercise Definition and 578 Threads

How can I select ( identify) the exercise which I have solve in Dummit book ? and avoid these exercises which I have not to solve ? I talk about Identified book " Dummit and Foote "

Homework Statement Suppose g(x,y)=f(x-y,y-s) Homework Equations Nothing else The Attempt at a Solution Find dg/dx + dg/dy

Homework Statement Please read the attachment =) All the formulas I was given are also on a separate attachment I initially thought the answer was the last one because I did rf-ri and subtracted across and got 0 mi + 25mj but I am not sure =[ Homework Statement

Here I am with another problem... :) It's from a Discrete Mathematics course and it requires a step by step proof with logical equivalences and deductions made based on the laws of logic. A,B,C and D are all on the same canoe team. They don't know what sitting order they should make and all of...

The Subject is Discrete Mathematics as part of a Computer Science major. The exercise is as follows: Erica, Stanley and Robert were all witnesses in a car crash. Their statements are contradictory to one another, and all of them claimed that someone else lied. Erica claimed that Stanley lied...

Hi, Knuth's TAOCP exercise 5.1.1-6 asks to construct an n-log-n algorithm which would generate an inversion table corresponding to a particular permutation. My algorithm constructs inversion table for a random permutation of 1..N numbers (Knuth, Volume 3, exercise 5.1.1-6) using binary...

hi, every one. i'm student in VietNam, and now, I'm studying about nucleat physsics. i don't know, can i post my problem in here? expect admin ok. my problem is: I'm studying a subjec what this book is Nuclear System I. my exercise is "steam generator tube type CE" ------ we have a steam...

Hi everybody, sorry for my sloppy english. I have to translate the task so if you don't understand something just tell me and I try to rephrase it. Homework Statement The exersice is about the "Knallgas" equation. Two reaction euqations are given: 2H + O \xrightarrow \ 2H_2O...

Homework Statement 5. Let ##A## be a nonempty set of real numbers which is bounded below. Let ##-A## be the set of all numbers ##-x##, where ##x\in A##.Prove that $$\inf A=-\sup(-A)\text{.}$$ Homework Equations The Attempt at a Solution Does the proof below look OK? I am a bit uneasy...

I'm taking Conceptual Physics, which is the first science course I've taken in college, and I cannot seem to understand the Exercise questions. For example, "You're in a car traveling at some specified speed limit. You see a car moving at the same speed coming toward you. How fast is the car...

Z-transform of a conjugated sequence ("a straightforward" exercise) Homework Statement The conjugation property is expressed as x^*[n] \stackrel{Z}{\leftrightarrow} X^*(z^*) This property follows in a straightforward maner from the definition of the z-transform, the details of which are left...

I'm having trouble with this exercise: If x is an element of real numbers, define B(x) to be the set of all numbers b^t, where t is rational and t<=x Prove that b^r=sup(B(r)) when r is rational. I had a proof by contradiction in mind, but I am having trouble furnishing it. Thanks,

Homework Statement The problem (18.1a) can be found here: http://www.suagm.edu/umet/paginas/dbacelo/chem464/scan-probcap18-levine-pag1.pdf . For reference, the equation (referred to as 18.2 in the problem statement) for the frequency distribution of blackbody radiation is give as...

Homework Statement Suppose a \in R^{k},b \in R^{k}. Find c \in R^{k} and r > 0 such that |x-a| = 2|x-b| if and only if |x-c| = r. Homework Equations Solution: 3c = 4b - a, 3r = 2|b-a| The Attempt at a Solution Technically, I can't seem to find any way to express |x-c| in terms of |x-a|...

Need help! MTW's Gravitation exercise 16.1! I am working on MTW's Gravitation and I came across a problem. In the attachment https://www.physicsforums.com/attachments/50292, I show my calculation and, finally, I show the contradiction that is, you can get a vanishing \Gamma^k_{\phantom{k}kk}...

I have some problems getting conditional probability right... Does this look like it should? Homework Statement Assume that there are bags of tulip bulbs in the basement, ant that they contain 25 bulbs each. yellow bags contain 20 yellow tulips and 5 red tuplips, and red bags contain 15 red...

Hi I wanted to know what your strategies and throughts are for keeping your life stable and minimizing stress. How does this affect your studies/work? Yes, sometimes stress can be the fire under your a** but obviously it's not sustainable. I find it's good to have routine in life, but if I...

Homework Statement Determine if the following set is a vector space under the the given operations. The set V of all pairs of real numbers of the form (1,x) with the operations: (1, y) + (1, y') = (1, y + y') k(1, y) = (1, ky) Homework Equations The Attempt at a Solution...

Homework Statement Determine if the following set is a vector space under the given operations. List all the axioms that fail to hold. The set of all pairs of real numbers of the form (x,y), where x >= 0, with the standard operations on R^2 Homework Equations The Attempt at a...

Hello, I would like to solve this exercise in the best way as possible. I solved using the most trivial way and I am in doubt if are there some better way to solve. Homework Statement Simplify: Homework Equations \left(x + \frac{1}{x} \right)\left(y + \frac{1}{y} \right) +...

One concept in physics that has never set well with me is the way work and energy are defined. According to all the physics sources I've looked at, work is defined as: W = \vec{F} \cdot \vec{d} (for a constant force over a distance) However, intuitively the notion of taking the dot...

Everyone knows college is tough. My professer suggested to me that I should daily do some strenous exercise for at least half an hour. I think he gave that suggestions, so that I could reduce my stress level and after exercise my brain will be fresh so I could study better. I on the other hand...

Homework Statement Hi guys, I don't reach the correct answer to an exercise. I'm following Ashcroft's book. I must find that the reciprocal of the bcc Bravais lattice is a fcc one and the reciprocal of the fcc Bravais lattice is a bcc one. Homework Equations If a_1, a_2 and a_3 are...

Please, can you check the following execution is correct? Problem text I have a plane in affine space in R^4 described by two following equations: \begin{Bmatrix}3x+y-z-q +1=0\\ -x-y+z+2q=0\end{Bmatrix} I have the coords of a point P: (0,1,1,0) Describe the locus of points Q such that...

Hi, I'm working on exercise 9.13 of the "bible" Gravitation. The problem I have is how to derive the following equation: R_x(t)R_z(\psi)R_x(\theta)R_z(\phi) = R_z(\psi-tsin\psi cot\theta)R_x(\theta+tcos\psi)R_z(\phi+tsin\psi/sin\theta) Where R_x(t) denotes an infinitesimal rotation about...

Hello! I'm here again, now with a new exercise! :biggrin: Homework Statement A block of mass m is at rest over this wedge (it's a triangle) of mass M that is at rest over a table. There is no friction. The point P of the block has a height h from the table. Then the block starts to move. What's...

Homework Statement Hello! I'm trying to solve this exercise: A bullet with initial velocity v and mass m pass through a block of mass M in a pendulum of length L and leave the block with velocity v/2. Which value of v will make the pendulum describe a circumference? As you can see, English is...

Hello, I'm given this linear transformation and I'm asked to do the typical calculations (kernel, image, dimensions, etc.) but there's one thing I'm not sure I understand, here's the exercise: f(1,0,0)=(-1,-2,-3) f(0,1,0)=(2,2,2) f(0,0,1)=(0,1,2) a) Is f invertible? b)Find a basis of...

Hey people, could someone solve this problem and explain step by step? It's from a past exame and I really need to know how to do it, tried everything I know (not much tho). Please don't omit steps.Really appreciated! imageshack.us/photo/my-images/403/dvidafrumdelgebra.png/

Homework Statement In the exercise 8.4 from Quarks and Leptons. An Introductory Course in Modern Particle Physics - F.Halzem,A.Martin we can see: if the charge distribution \rho(r) has an exponential form e^{-mr}, then: F(q) \propto (1 - \frac{q^2}{m^2})^{-2} where...

Homework Statement Let x=(x1,x2,x3), Ax:=(x2-x3,x1,x1+x3), Bx:=(x2,2x3,x1) Find: (3B+2A2)x. Homework Equations The Attempt at a Solution Warning: I have no idea what I'm doing! (3B+2A2)x = 3Bx+2A2x 3Bx = (3x2,6x3,3x1) Now to find 2A2x. Considering that an index has a...

Exercise on composites << please. this is going to be in my exam! PLEASE. I really need this! (im preparing the course by myself and have no one to ask to! a hose in a high-pressure water-jet cleaning system is to be made of a glass-reinforced polyethylene composite material,with continious...

Hi, Everyone. I have an electronics I exams tomorrow, and I'm looking for help in solving the following exercise if you don't mind. The exercise tells that this circuit is to be fabricated with a transistor type whose β is in the range of 50-150. It asks to find the value of Rc, so...

"Relativistic Mass" thought exercise with approaching bodies I understand that the concept of 'relativistic mass' is somewhat controversial, but for reasons that are unclear to me. Nevertheless, I humbly pose the following thought exercise/inquiry: For starters, I understand the formula for...

hi guys I'm a 2nd year undergrad doing astrophysics, and I was set this piece of coursework a couple of weeks ago, and it's due in a few weeks, so I'm getting started. Problem is, I don't know where to go with it. We've basically been given a load of data of measured fluxes in the U, B and V...

Homework Statement A uniformly charged wire or radius R1=0.02m runs down the axis of a cylinder of inner radius R2=0.06m. The potential difference between the wire and cylinder is 60 volts. Find the electric field at the surface of the wire. Homework Equations Electric flux=Q/\epsilon0...

When reading tips on various websites of how to "study physics" I always see they bring up exercise as being one of the key things to success. But, is it really that integral to one's success? I'm quite skinny and frail, and I've noticed most of my professors and other classmates aren't in shape...

Homework Statement Just click the link, The image is huge, so I did not use IMG tags. http://i.imgur.com/zWNRf.jpg Homework Equations Let's see, The rotational kinetic energy of a body is given as K = \frac{1}{2}Iω^{2} for a point mass, I = mr^{2} for a rigid rod rotating at it's end...

Homework Statement This is an exercise from 'How to Prove it - A Structured Approach' (Exercise 7a, page 54) . So far a a really great book. Homework Equations The DeMorgan, Absorption, Idempotent, Double Negation, Commutative, Associative, Distributive, Tautology, Contradiction...

I need a good book, or in other words a book and it's solution manual if available on line - in classical physics. Some Lagrange, Hamiltonian exercises, with good explanation. Thanks in advance.

Homework Statement A point particle moves in space under the influence of a force derivable from a generalized potential of the form U(r, v) = V (r) + \sigma \cdot L where r is the radius vector from a fixed point, L is the angular momentum about that point, and \sigma is a fixed vector...

Hi all. From Hoffman and Kunze's book Linear Algebra, page 27, exercise 12: What's the most elementary way to solve this? Any hint is appreciated.

As it is right now, I'm fairly certain I have E.I.A. I've setup an appointment with my doctor but the soonest I could get one was 2 weeks from now, so I've been trying to further educate myself on it so I could go in with a little bit better of an idea of what I think I have. At first I...

Hey guys, I've been given a worksheet with a couple of questions concerning radioactivity, half-life etc. It is high school level and for me, it seems like the first year doing physics as our current teacher is the first one who really knows something about the subject. :) So please be patient...

In Cooper's book, I can't think out the solution of the following exercise. Show that each creative set is contained in some simple set. By the way,they are not homework question. I read the book on my own and I am a beginner. Thanks for your hint.

Hi guys, It's been a while since high school, and now I'm faced with a problem I need to solve in a few days (attached). Would someone please help me through that? I would really appreciate support.

Homework Statement A bicycle tire is to start with flat and has a pressure of one atmosphere. It is then pumped such that the pressure is 4atm, when the air inside the tire has the same temperature as before. a) How much air has been pumped into the bicycle tire? b) What is the temperature of...

Homework Statement I apologize if this is not the right place to put this. If it is not please redirect me for future reference. 11. Consider a uniform thin disk that rolls without slipping on a horizontal plane. A horizontal force is applied to the center of the disk and in a direction...

I'm using the app on my iPod that's for myfitnesspal. Great app to help count calories. Also, I'm doing the Zumba exercise program to help with the weight loss/tone up. Any opinions on all of this??

YBa2Cu3O(7−x)(s) + ([ 7/2]−x)H2(g) → [ 1/2]Y2O3(s) + 2BaO(s) +3Cu(s) + ([ 7/2]−x)H2O(g) 35.937 ± 0.005 mg of solid YBa2Cu3O(7−x) reacts completely, according to the above equation, in a stream of hydrogen gas at 1000°C, leaving 33.242 ± 0.005 mg of solid residue. (For the purpose of this...