Value Definition and 1000 Threads

Homework Statement I am trying to solve the following: y'''-9y'=54x-9-20e^2x with y(0)=8, y'(0)=5, y''(0)=38 Homework EquationsThe Attempt at a Solution The right answer is: y= 2+2e^3x+2e^(-3x)-3x^2+x+2e^2x I am only wrong on the coefficients C2 and C3. Where did I mess up in my solution?

Homework Statement I am given (y^2 + y sin x cos y) dx + (xy + y cos x sin y) dy = 0, y(0) = π/2 . I need to solve this Homework EquationsThe Attempt at a Solution At this point they still aren't exact, so I gave up. I can't figure out what the problem is. Is it possible that I have to...

Hi guys! I am wondering if someone can help me with an assigment i got, i would appreciate if someone could help me with it. Find effective value and phase shift for the current I in the link the tip is to use the superposition theorem http://imagizer.imageshack.us/a/img924/3673/R5qIAN.png

$n\in N,\,\,and \,\, a_1,a_2,a_3,-------,a_n\in Z$ $if \,\, a_+a_2+a_3+-----+a_n=a_1\times a_2\times a_3\times------\times a_n=2006$ $find \,\, min(n)$

Consider the Lagrangian $$\mathcal{L} = \bar{\psi}(i\gamma^{\mu}{\partial_{\mu}}-y\phi)\psi +\frac{1}{2}(\partial_{\mu}\phi)^{2}-V(\phi),$$ where the potential energy ##V(\phi)## is given by $$V(\phi) = \frac{1}{2}\kappa^{2}\phi^{2} + \frac{\lambda}{24}\phi^{4}.$$ For...

Homework Statement If the average (arithmetic mean) of 3a and 4b is less than 50, and a is twice b, what is the largest possible integer value of a? Homework Equations Avg of two variables is: (a+b)/2 The Attempt at a Solution (3a + 4b)/2 < 50 3a + 4b <100 Now try out values such a = 2b I) a=...

$\tiny{242.14.2}\\$ $\textsf{(a) Verify that y = $Cx^2+1$ is a general solution to the differential equation $\displaystyle x \frac{dy}{dx}=2y-2$}$ $\textsf{(b) Use part (a) to solve the initial value problem $\displaystyle x \frac{dy}{dx}=2y-2, \, y(2)=3$}$ $\textit{all new so kinda ??}$

Let $a$ and $b$ be positive real numbers such that $a+b+\sqrt{2a^2+2ab+3b^2}=4$. Determine the maximum value of $a^2b$.

Homework Statement Given ##\psi = AR_{21}[BY_1^1 + BY_1^{-1} + CY_1^0]##, find ##\left<L_z\right>## and ##\left<L^2\right>##. (This is not the beginning of the homework problem, but I know my work is correct up to here. I am not looking for a solution, only an answer as to whether or not my...

Hey! :o I want to determine the present value of a perpetual annuity, which will incur an interest payment of € 1 at the end of each year. A calculative interest rate $r$ is assumed. We are at the time $t = 0$, the first payout is in $t = 1$. Could you explain to me what an interest...

I am trying to derive a scaling factor for an analog voltmeter for the purpose of measuring the secondary voltage of an electronic halogen transformer (EHT). http://www.ledbenchmark.com/faq/Transformers-Output-and-Compatibility.html The output voltage of these things is a "high frequency"...

sin\theta 3/5

There is a graph in the form of $x^2-2x-3$ determine the value of $\sqrt{3}$ to the nearest decimal place by drawing an a suitable straight line What must be that straight line ? Usually these kind of problems are solved using the quadratic equation Many thanks :)

Homework Statement Consider the following matrix. A = 2 + 4i...1 + 5i 2 − 3i...2 + 3i Let B = A-1. Find b12 (i.e., find the entry in row 1, column 2 of A−1) Homework Equations A-1 = 1/(ad - cb)* [ d -b ] [ -c a ] <--imagine as 2x2 matrix with first row (d,-b) and second row...

I have a matrix of data and I want to do SVD using excel, is it possible?

This question concerns a section from the book Modern Physics by James Rohlf. http://srv3.imgonline.com.ua/result_img/imgonline-com-ua-twotoone-Bs4zgy7pruqG.png He shows that the form of the Wave equation for light remains invariant under a Lorentz boost (4.42)...

Homework Statement Let Y_1,Y_2 be independent random variable with uniform distribution on the interval [1,2]. Define X=max{Y_1,Y_2}. Find p.d.f., expected value and variance. Homework EquationsThe Attempt at a Solution Since $X=\max\{Y_1,Y_2\}$, this tells $Y_1$ and $Y_2$ must at most $x$...

Homework Statement In a coherent state ##|\alpha\rangle##, letting ##P(n)## denote the probability of finding ##n^{\text{th}}## harmomic oscillator state. Show that $$\displaystyle{\langle\hat{n}\rangle \equiv \sum\limits_{n}n\ P(n)=|\alpha|^{2}}$$ Homework Equations The Attempt at a...

How do I begin proving: sum(k>=1)8/(k^4+4)=pi*coth(pi)-1? I got this from Mathematica. Thanks in advance for any help.

Hello everybody after a little while :D The roots of the equation $(x+a) (x-b)= 0$ are -3 or 2. Find the value of $a$ & $b$ What should I do here ? Many Thanks :)

Suppose I apply a particular function and I get a value of the cell-A1. How can I copy this value to another cell-C1 and the entire column under C1 to use it in a new operation provided that C1 and the entire column are always updated when A1 changes?

Obviously ##\mathbb{R^2}## is convex, that is, any points ##a,b\in\mathbb{R^2}## can be connected with a line segment. In addition, ##f## is differentiable as a composition of two differentiable functions. Thus, the conditions of mean value theorem for vector functions are satisfied. By applying...

Hello good evening to all, I was studying here and got stuck with this. I solved the integral and got [x+sin(x) -1] and that´s the farthest that I got. I would appreciate the help.

Homework Statement dy/dx= 200-2y. y(0)=75 Homework EquationsThe Attempt at a Solution Do you move dx over and integrate. Do you just integrate it 200y-y^2+c

Suppose ##\intop_{-\infty}^{+\infty}(f(x))^{2}dx=1##, and ##a=\intop_{-\infty}^{+\infty}(\frac{df(x)}{dx})^{2}dx##, does a maximum value of ##a## exist? If it exists, what's the corresponding ##f(x)##?

Hi. Is the Maxwell equation $$\nabla\cdot\vec{E}=\frac{\rho}{\varepsilon_0}$$ even true in the stronger form $$\frac{\partial E_i}{\partial x_i}=\frac{\rho}{3\cdot\varepsilon_0}\enspace ?$$ I guess not, since I haven't found a source suggesting this. But shouldn't the isotropic electric field...

Homework Statement s = 0.5(e^t - t - 1) t=? when s=18 Homework Equations the use of natural log probably The Attempt at a Solution I tried using the natural log rule but I am getting stuck. Please help me out here. If someone could give a step by step solution,I'll be rreally glad, Cheers

Homework Statement What will the pointer of electrodynamic ammeter show (its natural frequency of oscillation is 5 Hz), if its input is energized by current: a) i (t) = 1.5 + 4 sin (3146 t) b) i (t) = 1.5 + 4 sin (2 t) Ammeter has a range of 6 A and the scale has 100 divisions. Homework...

Homework Statement A fuel gas consists of 75% butane (C4H10), 10% propane (C3H8) and 15% butene (C4H8) by volume. It is to be fed to the combustion chamber in 10% excess air at 25°C, where it is completely burnt to carbon dioxide and water. The flue gases produced are to be used to generate 5...

If $log_a 2 = P $ & $ log_a 3 = q$ find $log_a 72 $ in terms of $p$ & $q $ I'm not sure on how to begin this may be convert the logarithms to decimals :confused: Many Thanks :)

Homework Statement Use the Intermediate Value Theorem to prove that any continuous function with domain [0,1] and range in [0,1] must have a fixed point. Homework Equations Intermediate Value Theorem (IVT) states that if a function ##f(x)## of domain [##a,b##] takes values ##f(a)## and...

Hello everyone! I'm confused because 90% and 35% obviously do not add up to 100% and as a result I'm really flustered! :C I appreciate the help and efforts of everyone on this website! :D

Homework Statement Find $$\sum_{k=1}^{64} {64 \choose k} 64k$$ Homework Equations Not sure The Attempt at a Solution Please give me hint how to start doing this question

hi, i have a question which i was hoping someone could help with,a series circuit featuring a capacitor (C) charging via a 1Mohm (R) resistor and a 12volt dc supply(VS).i know the equation to describe VC is VC=VS(1-e -t/RC)the question is: assuming VC is 2V after a time of 4 seconds, determine...

Hello, I was researching the Planck Constant values and decided to build a math software to scan for potential values that relate to permittivity of free space and permeability of free space and found one of the 2010 CODATA values (specifically the Magnetic Resonance Imaging value). Can I get...

Homework Statement If a ball is dropped from a height (H) its velocity will increase until it hits the ground (assuming that aerodynamic drag due to the air is negligible). During its fall, its initial potential energy is converted into kinetic energy. If the ball is dropped from a height of...

Hi, I am running a fortran 90 program and I have some problems when getting an average. It happens that at some point the value of suma2 is not updated, even when the value of the term s(fixed2(j))/real(nfixed) is not zero. Below is the output of fort.32. The problem dissapears when suma2 is...

Homework Statement f(x)= (sincx/x) ; x<0 1+(c)(tan2x/x) ; x≥0 Homework EquationsThe Attempt at a Solution Lim as x tends to 0+[/B] = 1+c⋅2⋅(sin2x/2x)⋅(1/cos2x) =1+c⋅2⋅1⋅1= 1+2c Lim as x tends to 0 - = (sincx/x)=(c/1)⋅(sinx/x)=c⋅1=c Equating both: 1+2c=c...

This isn't really a question for which the template is useful.. Can anyone explain to me why the value of the variable 'seed' in location 1 is different from the value in location 2? The only thing happening in between is the defining of the varaible v(1) using the real function. I don't see...

What I know, $\angle RQS=25^\circ$(Inscribed angle theorem) & $\angle RSP=110^\circ$(opposite angles of a cyclic quadrilateral add upto 180) $\angle TSP=70^\circ$(angles on a straight line add upto 180) (Happy) Many Thanks

Title field did not accept all of title: Value or what one can do with astronomy or astrophysics education What is the real-world, employment value and meaning of a degree in Physics if a student concentrates on astronomy or astrophysics, meaning his employment value? What about such a degree...

Mass of a book of type X = 40g; Mass of a book of type Y=80g; The total mass of n books of type X and one book of type Y is less than 200g; i. Write down an inequality containing the variable n only. ii. Solve the above inequality for n and write down the maximum possible value for n So how...

Homework Statement The function ##f(x)=2a^2x\left(x-a\right)^2## intersects with the line ##y=ax## at the origin, point ##Q(b,f(b))## and point ##T(c,f(c))## where ##c>b>0##. A probability density function, ##p(x)=ax-f(x)## can be formed over the domain ##[b,c]##. (a) Determine the exact...

(Mentor note: moved from another forum hence no template) For what value of the constant c is the following function continuous at x = −3? f(x)=(1/x+1/3)/(x+3) if x≠ -3 f(x)=c if x=-3please provide proof... I am so confused:(

Hello, I am finding this questions quite difficult, can someone please offer some insight as to what needs to be done. Do we need to do limit tests to the left and right of x = 7?

Upto what maximum height, value of g remains equal to 9.8 or close to it. g = GM/r^2 And g' = GM/(r+h)^2 = g/(1+ h/r)^2 Therefore when h ≥ r , g' decreases Again if h < r , g' agin decreases BUT I want to know what is the maximum height at which g' ≈ 9.8 From my calculation maximum height...

How do I determine the value of a blocking capacitor for say this circuit: What I mean is, sure Cin must behave like a short circuit at working frequency, but something tells me there is more to the choice of a coupling capacitor than this.

Any ideas ? (Tauri)

Considering the expansion of $(x-y)^3$ , Find the value of $2\left(24^3-3*24^2*4+3*24*4^2-4^3\right)$ Any Ideas on how to begin ? (Mmm)

Hi, For school we are currently working with heterogeneous equilibria. I am given a salt that will be solved in water and I have to calculate the concentrations of the ions. I have to use the solubility product for this. In the Netherlands we are provided with a reference book that has all...