Positive Definition and 963 Threads

In what regard might positive infinity be equivalent to negative infinity?

Homework Statement I hope that I'm going to make sense here. I found the Jacobian of two functions by taking the partial of F1 w.r.t x, then y and same for F2. My professor did it by taking the partial of F1 w.r.t. y, then x, same for F2. So I have a 2x2 matrix. When i go to find the...

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Homework Statement Prove that if n is an odd positive integer, then n^2\,\equiv\,1\,\left(mod\,8\right). Homework Equations Theorem: a\,\equiv\,b\left(mod\,m\right) if and only if a\,mod\,m\,=\,b\,mod\,m The Attempt at a Solution Using the theorem above: a\,=\,n^2 b\,=\,1,\,m\,=\,8...

Homework Statement First, I'll give a problem in context.. In anticipation of her first game, Alesia pulls back the handle of a pinball machine a distance of 5cm. The force constant of the spring in the handle is 200N/m. How much force must Alesia exert? Convert 5cm to 0.05m. F=kx...

I need to draw a single point charge with a magnitude of +4.3 C (coulomb's) I want to make sure that I am doing this right so: If one electron equals 1.602*10^-19 C than +4.3 C is actually a negative charge and therefore -4.3 C would be a positive charge. Is this right or do i have it...

Let K = A^T C A, where C>0. Prove that kerK=cokerK=kerA, and rngK = corngK = corng A. I sort of need a kickstart to get going. I know that each element will be K_{ij} = v_i^T * C * v_j, so this is sort of like a Gram matrix, which in turn also means that the matrix is semi-positive definite...

i want to prove that for every positive integer k, we can find such a positive integer n, such that k divides n and n is only composed of the digits 0 and 3. i don't have any idea how to approach this problem. any help will be appreciated. thanks in advance.

Someone once said that a positive hydrogen ion in a solution is not just a proton. When queried he replied by explaining that a positive hydrogen ion in solution will have a relatively high charge density because of the small ionic radius. I can't see any difference: a proton and a positive...

The net force on a moving positive charge... Homework Statement A magnetic field has a magnitude of 1.2 x10^-3 T, and an electric field has a magnitude of 5.4 x10^3 N/C. Both fields point in the same direction. A positive 1.8 µC charge moves at a speed of 2.9x10^6 m/s in a direction that is...

Question: Which of the following would probably have a positive delta S value? He (g, 2atm) --> He (g, 10 atm) H2(g) + I2(s) --> 2HI (g) 2Ag(s) + Br2(l) --> 2AgBr(s) O2(g) --> O2(aq) 2NO2(g) --> N2O4(g) My answer: Well, I know that when a gas is pressurized, there are less states it...

Homework Statement Show that the positive quadrant Q = ( (x,y) | x,y > 0 ) \in \mathbb{R}^2 is a vector space. Homework Equations Addition is redefined by (x_1,y_1) + (x_2,y_2) = (x_1 x_2, y_1 y_2) and scalar multiplication by c(x,y) = (x^c , y^c) The Attempt at a Solution There...

Can we, in principle, consider electrons as positive charges and protons as negative charges? How would our laws change if that was the case? Do you guys think that the convention of choosing electrons as negative charges and protons as positive changes was a mistake? Do we really need...

Homework Statement The integral of f on [a,b] exists and is positive. Prove there is a subinterval J of [a,b] and a constant c such that f(x) >= c > 0 for all x in J. Hint: Consider the lower integral of f on [a,b] Homework Equations The Attempt at a Solution I don't see how...

Homework Statement A long line carrying a uniform linear charge density 50.0 microcoulombs/m runs parallel to and 10.0 cm from the surface of a large, flat plastic sheet that has a uniform surface charge density of -100 microcoulombs/m^2 on one side. Find the location of all points...

Hello All, Here's a strange question for you. Is there any possible way to add two or three sine wave functions together so that the resulting wave never goes below the positive Y axis of the graph? These functions can be whatever frequency or phase necessary, just no vertical offset. I am...

Homework Statement I have some problems determining the tension output value for this circuit and this confusion comes from the presence of positive feedback and an alternate current.Since I'm used to negative feedback circuits and direct current it confuses me a bit,so any help is deeply...

I was wondering,how does positive feedback works in opamp circuits?Like is there any formula for calculating positive feedback?I know that with negative feedback we have Vp=Vn but I don't know how it works with positive feedback!Thanks for the reply!

I need help proving that the following (double) integral is positive: int(limits from -infinity to +infinity) f(b) int(limits from b to +infinity) [e^{-(x-mean)/(2 *variance)}]/sq root(2 *pi *variance) dx db thanks

Hello I'd like to know how to prove that the trace of A.A* is positive. I don't really know how to handle the imaginary part of it. If A has any complex number in it, is it possible to get traces like 10-2i? If yes, do I consider it as a positive number or negative?:zzz: Thanks in advance

Simple question. Are reference angles always positive??

"A rope exerts a force on a bucket as the bucket is raised up a well." Is the work done on the bucket positive or negative? Now, I know that the is a tension force in the rope that must overcome weight to accelerate the object up the well. Also, work is positive if the force exerted is in the...

Let (infinity)(sigma)(n=1) = An be a series with positive terms such that lim(n -> infinity) = (An+1)/(An) = L < 1 a) Let L < r < 1. Show that there is an N > 0 such that for all n > N, we have (An+1)/(An) < r b) Show that Ak+N < or = ANr^k for k = 1, 2... c) Show that lim (k ->...

I know that gravitational energy is a delicate topic in GR. It is true that the localisation of gravitational energy is not possible in GR but it should at least be possible to determine correctly the sign of the gravitational energy. I found the following article in arxiv.org, nl...

Can you tell me the answer to this question? Why would the scientific community resist the concept of a nucleus full of positive charges and what observations helped them explain this design. Thanks, v

alright so here is the problem. The parabola y=x**2+3 has two tangents which pass through the point (0,–2). One is tangent to the to the parabola at (A,A2+3) and the other at (–A,A2+3). Find (the positive number) A. i've attempted this problem several times but haven't been able to find the...

hi, I found this problem in Rudin, and I just can't figure it out. It goes like this: Prove that the convergence of \sum a_n a_n \geq 0 implies the convergence of \sum \frac{\sqrt{a_n}}{n} I tried the comparison test, but that doesn't help because I don't know what the limit \lim_{n...

Hello everyone. I'm trying to set this problem up to prove by induction but having some issues. Suppose that for some Predicate P(k), you first prove that P(1) is true, and then you do the following. You prove that, for every positive even integer k, if P(i) is true for all odd integers i...

today is my first day here so if i violate any rule that apply in this forum please forgive me.. the question is Dr. Silverstein is driving a 1.95 * 10^3 kg car at 55.0Km/hr. He slams on the brakes and comes to rest in a distance of 17.0 m Assume that Dr. Silverstein has a mass of 75.0 kg...

hello everyone, I have a problem, if anyone can get me started. Thanks I have to show this equality knowing that a and b are positive and they do not euqal 0: (a^{2}+a^{\frac{4}{3}}b^{\frac{2}{3}})^{\frac{1}{2}} + (b^{2}+a^{\frac{2}{3}}b^{\frac{4}{3}})^{\frac{1}{2}}...

I'm trying to create an algorithm in MATLAB, but I have a problem. According to theory, if G is a positive definite matrix, then it's eigenvalues are positive real numbers. I'm using function EIG() to calculate the eigenvalues and eigenvectors of matrices, but I almost always take and negative...

http://i5.tinypic.com/4hionb9.jpg Please check my answers a) I know that e^x^3 > 0 and for all x ∈ [-1, 1], so we have ∫[-1 to 1] e^x^3 dx > 0. But how would you explain in words? b) For all x ∈ [0, 1] , 0 ≤ x^2 ≤ x , so e^0 ≤ e^x^2 ≤ e^x Therefore ∫[0 to 1] e^0 dx ≤ ∫[0 to 1]...

Do you consider ugliness a misery? Do you think is there any nice thing about being ugly?

I have a physics question that states: An amount of positive charge is distributed uniformly along the positive y-axis between y=o and y=a. A negative point charge -q lies on teh positive x=axis a distance r from the origin. Derive the x and y compontes of the force that the charge distribution...

lee smolin claims that SUSY/string theory can account for negative (anti-DS) and zero cosmological constant, but not a positive de-sitter constant, which is what has been observed. he also claims the kodama state in LQG has a good semiclassical limit that is GR, and incorporates a small...

How do you solve quadratic equations which have atleast one positive root?? The question was this: Find the value of 'm' for which the roots are such that at least one is positive. x2 -(m-3)x + m = 0 mR. Can someone help me get started? Here is my work: I checked the discriminant. for...

Cancellation or generation of positive energy by negative energy and vice versa is so often brought up by very serious physicists (e.g. A. Guth, A.V. Fillipenko) as the argumentation for the possibility of the generation of our universe out of “nothing”, that I hardly dare to question this. As...

I just can't justify this in my simple mind. I just always accepted it because I was told that it is equal to 1 throughout high school, and now in cegep. :confused:

An Hermitian matrix H is positive definite if all its eigenvalues are nonzero and positive. Assume that the matrices A,B are positve definite, and that the difference A-B is positve definite. Now, for which unitary matrices, U , is it true that the matrix A-UBU^{\dagger} is positve...

Aside from early diesel engines, does anyone know of brayton-cycle engine that uses a positive displacement compressor rather than an aerodynamic one?

What materials for positive pole, negative pole and what acid when put together create a perfect battery? (I'm not talking about everyday purpose for a batery (so never-mind how bio-hazardous a material is), but a theoretical (greatest voltage, greatest current possible, yet stable enough (so...

Hello everbody I have functions of two variables and I need to determine if they are positive or negative. I am just wondering if anyone can tell me what the best way to do that is? Thanks a lot in advance

An object of mass 2 kg is repelled from the origin by a force in the +x-direction whose magnitude varies with x according to F=(7Nxm^2)x^-2. How much work is done by this force when the object moves from x=2 to x=3? (Be sure to say whether this work is positive or negative.) I have no idea...

how do you prove the set of vectors "all ordered quadruples of positive real numbers" make a vector space?

A region in space contains a total positive charge Q that is distributed spherically such that the volume charge density rho (r) is given by: rho (r)=3 * alpha * r /(2R) for r ≤ R / 2 rho (r)= alpha * [1-(r/R)^(2) ] for (R/2) ≤ r ≤ R rho (r)=0 for r ≥ R Here alpha is a positive...

I need some help in finding a way to solve the following problems.: - Two equal positive charges q are on the y axis, one at y= +a and the other at y= -a. a) Show that the electric field on the x-axis is along the x-axis with Ex= 2kqx(x2 + a2)-3/2. b) Show that near the origin, when...

I have three math problems that I am unsure of how to do. could someone please help thanks. \sqrt[3]{-8x^3y^3z^3} ({4xy^-1}/{16xy^2}) \sqrt{98}+\sqrt{2}

I have been asked to explain without evaluating the integrals why 1) the integral of x cos x from 0 to pi/2 is positive and the integral of x cos x from pi/2 to pi is negative. And also would I expect x cos x from 0 to pi to be positive, zero or negative? And why ? 2) to find the...

4 to the power of 27 + 4 to the power of 1000 + 4 to the power of x. x is the maximum positive integer and it adds up to a perfect square?

Question goes as follows: "In an ionised gas there are positive ions and electrones moving around in collision with molecules of the gas. Calculate the ratio of the mean free path of the electrons in the gas to the mean free path of the positive ions in the gas." As far as I can see I...