Value Definition and 1000 Threads

Hi. I was just curious about the current value of the cosmological constant. My astrophysics class lecture notes say on the order of 10^-122, but the Wikipedia article says 10^-35 s^-2. Could someone explain where the 10^-35 s^-2 value comes from? Thanks!

how do i evaluate say a definite integral from [-3,3] of |x+1|? Any advice? I'm so confused.

Hey! :o We have the following initial value problem: $$x' = \frac{1}{2}(45 − x) + \frac{1}{4}(y − x) \\ y' = \frac{1}{4}(x − y) + \frac{1}{2}(35 − y) + \frac{1}{2}(z − y) + 20 \\ z' = \frac{1}{2}(y − z) + \frac{1}{2}(35 − z)$$ This can be written as follows: $$\begin{pmatrix} x\\ y\\...

Let $A,\,B$ be acute angles such that $\tan B=2015\sin A \cos A-2015\sin^2 A \tan B$. Find the greatest possible value of $\tan B$.

Homework Statement Show that E must exceed the minimum value for V(x) for every normalizable solution to the TISE, Hψ = Eψ Hint: rewrite the TISE as d2ψ/dx2 = (2m/ħ)(V(x) - E) Homework Equations I understand how to get the TISE Hψ = Eψ into the form of the hint by using the hamiltonian and...

Homework Statement $$ \int_0^{\pi} \frac{x(sinx)^{2n}}{(sinx)^{2n}+(cosx)^{2n}} $$ = A) π2 B) 2π2 C) π2/4 D) π/2 Homework Equations $$ \int_0^π f(x)dx = \int_0^π f(a-x)dx $$ The Attempt at a Solution If we put n = 1, we get the C option π2/4 But is it true for all n?

Homework Statement If a,b,c are three -zero vectors such that each one of them are perpendicular to the sum of the other two vectors, then the value of | a, b, c|2 is |a|2 + |b|2 + |c|2 |a| + |b| + |c| 2(|a|2 + |b|2 + |c|2) ½(|a|2 + |b|2 + |c|2) Homework Equations a.b = ab cosθ |axb|= ab sinθ...

Homework Statement Consider the equation: 3logx5+2logx2-log1/x2=3 a)State which values of x for which the equation is defined. b)Solve the equation for x. Homework EquationsThe Attempt at a Solution 3logx5+2logx2-log1/x2=3 =logx53+logx22-log1/x2=3 =logx125+logx4-log1/x2=3 =logx500-log1/x2=3...

Let (-3, 2) be a point on the terminal side of θ. Find exact values of cosθ, cscθ, and tanθ? Can anyone help!?

Let $[a,b]$ be a closed real interval. Let $f:[a,b] \to \mathbb{C}$ be a continuous complex-valued function. Then $$\bigg|\int_{b}^{a} f(t)dt \ \bigg| \leq \int_{b}^{a} \bigg|f(t)\bigg| dt,$$ where the first integral is a complex integral, and the second integral is a definite real integral...

What is the unit value of coulomb constant(k)? I just want to know the CGS unit value of k. In my book it is said the CGS unit value of k is 1. By i don't know how it come.?

so I'm doing a little project in solar thermal energy and I want to do the calculations before I start anything. I am stuck on getting the value of the pressure of the water inside the absorber when the temreture gets to 350 C. Is there a way to calculate it using thermodynamics table or...

Homework Statement I read this line in my textbook: "##PbS,CdS## are precipated in dilute solution only due to higher ##K_{sp}##" And I googled about the relation between solubility and ##K_{sp}## and I found that: "More is the ##K_{sp}## of a salt more it is soluble in a solution(I think...

In ring theory, a polynomial over a rings, say ## R[x] ## is presented as an abstract object of the form: ## p(x) = a_{n}x^{n} + ...+ a_{1}x + a_{0} ## where the coefficients ## a_{n}...a_{0} ## are from a ring R with unity and ##x## is a formal symbol. So what is the significance of ## p(x+1)...

Homework Statement Demonstrate that the expectation value of momentum (p) for the wave function: ψ(x)∝e^(-γx) when x>0, ψ(x)=0 when x<0. Hint: Pay special attention to the discontinuity at x=0.[/B] Homework Equations <p>=<ψ|p|ψ>=∫dxψ*(x)[-iħ∂/∂x]ψ(x) from -∞ to ∞. [/B]The Attempt at a...

Homework Statement Homework Equations The Attempt at a Solution http://imgur.com/7TRWjBg I don't really get what it's asking. I don't know how to define a Fourier series when the boundaries for X are between non-multiples of Pi. On top of that, it has one boundary that has 4<x<2Pi. How can...

For any positive real numbers a, b such that $a+b=1$, the inequality $(1+\frac{1}{a})(1+\frac{1}{b})\ge k$. Find the maximum value of $k \in \Bbb{R}$. I did: $(1+\frac{1}{a})(1+\frac{1}{b})= \frac{a+1}{a} \cdot \frac{b+1}{b}=\frac{ab+a+b+1}{ab}= 1+\frac{2}{ab} \ge k$ Using the Cauchy's...

Homework Statement Finding the critical value of shear stress at the junction and at the neutral axis Homework Equations stress max = (Bending moment x height from neutral axis)/Moment of inertia Shear stress = Shear force/area The Attempt at a Solution I am able to do the first 2 parts but...

Homework Statement The largest value of r for which the region represented by the set { ω ε C / |ω - 4 - i| ≤ r} is contained in the region represented by the set { z ε C / |z - 1| ≤ |z + i|}, is equal to : √17 2√2 3/2 √2 5/2 √2 Homework Equations complex number = a + ib where a,b ε R The...

I'm trying find the minimal polynomial of $$a=3^{1/3}+9^{1/3}$$ over the rational numbers. I am currently going about this by trying to construct a polynomial from a (using what I intuitively feel would be a sufficiently small number of operations). Then I'd show it's irreducible by decomposing...

In the wikipedia page of Lorentz Transformation (http://en.wikipedia.org/wiki/Lorentz_transformation#Lorentz_transformation_for_frames_in_standard_configuration) it's said that The problem I'm having here is that while taking Lorentz Transformation as true, I failed to verify the statement...

Find the maximum integral value of $k$ such that $(k-4)(x^2+x+1)^2-(k-3)(x^2+x+1)(x^2+x+2)+(x^2+x+2)^2=0$ has at least one real root for $x$.

Determine the minimum of $y$ where $y=|x-1|+|2x-1|+|3x-1|+\cdots+|nx-1|$.

Homework Statement Show that sin(2θ) / (1 + cos(2θ) = tan(θ) - I've completed this part Hence find the value of cot(π/8) in the form a + b√(2), where a, b ∈ ℤ Homework Equations cot(θ) = (1 + cos(2θ)) / sin(2θ) The Attempt at a Solution I did the math, got (1 + cos(π/4)) / sin(π/4) = (1 +...

Homework Statement The potential difference Δϕ between the plates of a spherical capacitor is kept constant. Show that the electric field at the surface of the inner sphere will be a minimum at a = b/2, where a is the radius of the inner sphere and b is the radius of the outer sphere. Homework...

Hello, I am analysing hydrology data and curve fitting to check the best probability distribution among 8 candidate distribution. (2 and 3 parameter distributions) The selection is based on the lowest AIC value. While doing my calculation in excel, how is it suggested to treat very low (approx...

I want to take the arg max over a number of functions as below, however it is possible that there are multiple i's for which the result is maximal. How do i denote that I want to take the last possible i, for example if it results in 3 and 5 I want it to return 5, is there notation available for...

Particularly, I mean trained skills rather than traits. For example, for a blank student/graduate who knows only physics theory, learning LaTeX would put them a little bit ahead. Then maybe some programming, learning simulation software etc. I'm finishing up my 2nd year in undergraduate right...

Homework Statement Prove the Mean Value Theorem for integrals by applying the Mean Value Theorem for derivatives to the function F(x) = \int_a^x \, f(t) \, dt Homework Equations [/B] Mean Value Theorem for integrals: If f is continuous on [a, b], then there exists a number c in [a, b]...

Hi all, Here is my story. My school offers BA and BS for both physics and math. I am currently a junior in the BS programs for both physics and math. The only difference between the two are merely the language courses verses the two science and society courses (S&SC). I have been told about the...

I have an inner product ## \langle \alpha|f| \beta \rangle## where ##f## is an operator that is a function of position ##x## operator (1D). According to the book I read (and I'm sure in any other book as well), that inner product can be written in position representation as ## \int...

A neutral atom of radium isotope may be represented by: 228 Ra (88 proton number, 228 nucleon number). 88...

Homework Statement Show that a real valued wavefunction ##\psi(x)## must have ##\langle \hat{p}\rangle = 0##: Show that if we modify such a wavefunction by multiplying it by a position dependent phase ##e^{iax}## then ##\langle \hat{p}\rangle = a## Homework Equations ##\hat{p} = -i \hbar...

Homework Statement Two identical particles, each of mass m are located on the x-axis at ## x=+x_0 ## and ## x = -x_0##. At what point (or points) on the y-axis is the magnitude of ##\vec g ## a maximum value and what is its value there? Homework Equations Formula for gravitational field...

So I was helping my sister on homework and there was this problem: 2 abs(2x + 4) +1 > or equal to -3 teacher told her to ignore the -3 and just set it equal to zero. Soo should you? This question got me confused. can't you just go about solving, bringing the 1 to the left and then dividing by 2...

Hey guys, nice to meet you all! My name is Jonathan and I'm from Queensland Australia. I'm currently working on a project which is seeking to find the most accurate method to value an asset based on historical stats. I think the best way to describe would be to provide a theoretical example: I...

Homework Statement I will denote operators by capital letters. The question is calculate <p | XXPP | x> / <p | x > Homework Equations X |x> = x |x> P |p> = p |p> P |x> = -i(hbar)d/dx X |p> = i(hbar)d/dp The Attempt at a Solution If I start on the RHS and take PP out I get...

Homework Statement A 2.0-kg body moving along the x-axis has a velocity vx = 5.0 m/s at x = 0. The only force acting on the object is given by Fx = (–4.0x) N, where x is in m. For what value of x will this object first come (momentarily) to rest? Homework Equations 0.5 mv^2 = KE F*d = work...

Homework Statement These are the pre lab tasks for my upcoming lab. Find the theoretical value for moment of inertia for a ring with off axis rotation using parallel axis theorem and outline procedure to obtain experimental value of I. During the lab we will be using a rotating platter with a...

Homework Statement For the equation y=-4e^t -4/3-2t+Ce^(3t/2), find the initial value y(0)=y_0 that separates solutions that grow positively as t -> infinity from those that grow negatively. Homework Equations (All are given in the problem statement.) The Attempt at a Solution I have half...

The derivative of ##|f(x)|## with respect to ##x## is ##f'(x)## for ##f(x) > 0## and ##-f'(x)## for ##f(x) < 0##. However, it is undefined wherever the value of the function is zero. I was wondering, though, if the product of this "undefined derivative" and zero is zero.

Hey thanks for reading:) I'm trying to learn calc and I thought it would help if I could figure out how to do this... For school I have a physics paper on artificial gravity and how it could work... I didn't post this in HW help because It's more of a written thing and I just got sidetracked...

For the problem of differentiating ##y = x^5(3x-1)^3## using logarithmic differentiation, the solution provides the first step as rewriting the functions as ##\left |y \right | = \left | x \right |^5 \cdot \left | 3x-1 \right |^3##. This confuses me. First, how are we, mathematically, able to...

Good morning everyone, I would really be pleased with a quick answer because I am very soon going to school. I have been asked to plot a graph, for that I am given a table with time in minutes from 0 to 6 on the first row. On the second row I was given activity in counts per minute with values...

Problem statement, work done, and equations: I cannot figure how to get the other resistor values, seems like too few knowns A Wheatstone Bridge is often used in sensor circuits and other measurement circuits. The basic circuit is drawn below: In the circuit, Rs is the sensor and might be a...

I'm working on a project where I have about 120,000 sources and my supervisor has told me to work out what significance to use for taking results. I had set it at 3 sigma. But there's roughly 1 in 500 chance that we will get a 3 sigma result by chance. I've been looking for a table to compare...

Hey guys, I got accepted to a few Cal State Computer Science masters (MS) programs (I live 10 minutes from one of them). I also applied to UC Davis and UC Irvine for their BS in Computer Science (would be a 2nd bach. degree, first was Psychology, pre-req's done/am doing at a CC), and am waiting...

Hey all, I'm currently building a 8 bit CPU and ram in simulator software but have no idea how to call a specific memory cell, ie I can't call the "001"(binary) cell, I'd want it to be translated to call the 4th cell. How does real ram solve that issue? Any help appreciated, thanks.

Show that the equation $|4x-5|-|3x+1|+|5-x|+|1+x|=0.99$ has no solutions.