Value Definition and 1000 Threads

  1. Buzz Bloom

    Question regarding published value for physical constant re photon density

    I searched for, but could not find any name or published value for a constant (with units m-3 K-3) which when multiplied by temperature (in degrees Kelvin) cubed gave the corresponding photon density (in m-3). Does anyone know of such a constant with a published value? I calculated a value, but...
  2. Y

    Finding the maximum value of a function

    Homework Statement Find the extremizing (maximum) value of the function f(x) = sin x / x using Newton's 1D method. Homework Equations [/B]The Attempt at a Solution I know the maximum point in this equation is (0, 1). When I differentiated the equation twice and used the formula above, I...
  3. N

    Torque value needed to move a particular vehicle

    can i know how much torque is required to move a 200kg weighed vehicle to 30kmph by using 24v, 250w dcmotor
  4. phy9

    Excel formula for rounding a value & error

    I'm having a physics lab in which a report needs to be submitted after an experiment. The experiment includes many measurements: values with their errors. I need to round the error up to 2 significant digits, and then to round the value up to to the amount of digits that the error is presented...
  5. King_Silver

    Initial Value Problem (complex example)

    I know the method and can solve other initial value problems. This is the question given: dy/dx + y(-2) Sin(3x) = 0 for t > 0, with y(0) = 2. I've brought the dy/dx and let it equal to the rest of the expression so it is now: dy/dx = -y-2 Sin(3x) , with y(0) = 2 (i.e. when x = 0, y = 2 ) The...
  6. karush

    MHB Is the given function differentiable at the endpoints on the interval [0,5]?

    Does the function satisfy the hypothesis of the mean value theorm On the given interval, give reasons for your answer $$f\left(x\right)=\sqrt{x\left(5-x\right)},\ \ \left[0,5\right]$$ The graph of this is the top half of a circle My answer was It is continuous at all points on the...
  7. C

    Principal value of an integral

    Can anyone tell me what is the principal value of an integral? The integral in this case is a surface integral?
  8. Inventermark

    Calculating Torque for a 24in Single Wheel Vehicle

    Need torque for single 24in wheel vehicle weighing 150lbs to reach top speed of 25 mph in 5 sec. So far I have got wheel rev of 350 per minute but not sure of torque in Ft lbs
  9. S

    Finding the value of A and B (Another problem)

    Hello experts, I have attached the figure below kindly see it. And here is my calculation, Using law of sine, from figure we can say that α+β=120° and β=120°-α and sin(β)/sin(α)=PA/PB=3/40=0.075 so, sin(120°-α)=sin(120°)cos(α)-cos(120°)sin(α) since, sin(β)=sin(120°-α) so...
  10. Odious Suspect

    When to introduce absolute value in hyperbola expression?

    We begin with this definition of a hyperbola. \left(\overline{F_1 P}-\overline{F_2 P}=2 a\right)\land a>0 Perform a few basic algebraic manipulations. \sqrt{(c+x)^2+y^2}-\sqrt{(x-c)^2+y^2}=2 a \sqrt{(c+x)^2+y^2}=2 a+\sqrt{(x-c)^2+y^2} (c+x)^2+y^2=4 a^2+4 a \sqrt{(x-c)^2+y^2}+(x-c)^2+y^2...
  11. S

    Find the value of point A and B

    Hello experts. I am attaching the image below. Kindly tell me how to calculate the values of A and B in the given figure? Now I must find A and B. How to get it? PS: P=-2.5+4.33i. But A is not at -2.5. Means PA is not making angle 90 with real axis. Thank you
  12. F

    MHB Finding Least Value m with Property P in Discrete Math

    Consider a set X with |X|=n≥1 elements. A family F of distinct subsets of X is sad to have property P if there exist A and B in F, such that A is a proper subset of B and |B\A|=1. Determine the least value m, so that any F with |F|>m has property P. This is a problem asked by our Discrete...
  13. Julio1

    MHB Laplace equation and Median Value Property

    Suppose that $u$ is the solution of the Laplace equation $u_{xx}+u_{yy}=0$ in $\{(x,y)\in \mathbb{R}^2: x^2+y^2<1\}$ $u(x,y)=x$ for all $(x,y)\in \mathbb{R}^2$ such that $x^2+y^2=1.$ Find the value of $u$ in $(0,0).$ Use the property of median value.
  14. D

    Expectation value of spin 1/2 particles along different axes

    Homework Statement Show that for a two spin 1/2 particle system, the expectation value is \langle S_{z1} S_{n2} \rangle = -\frac{\hbar^2}{4}\cos \theta when the system is prepared to be in the singlet state...
  15. O

    MHB Limit of Absolute Values and Metric Spaces

    Let $\lim_{{k}\to{\infty}}d\left({x}_{m\left(k\right)},{x}_{m\left(k\right)-1}\right)=\varepsilon$ and $\lim_{{k}\to{\infty}}d\left({x}_{n\left(k\right)},{x}_{m\left(k\right)}\right)=\varepsilon$...Can we say that...
  16. RJLiberator

    Quantum Measurements: The Average value is the cosine

    Homework Statement We know: In a measurement of quantum mechanics (basic) the average value is the cosine of the angle between the orthonormal basis of the measurement apparatus and the qubit (vector) entering it. Question: How do we prove this?Homework EquationsThe Attempt at a Solution Can...
  17. lulzury

    RLC Circuit time for Energy to drop to 20% of initial value

    Homework Statement In an oscillating series RLC circuit, with resistance R and inductance L, find the time required for the maximum energy in the capacitor during an oscillation to fall to 1/5 its initial value. Assume q = Q at t = 0 Homework Equations ## U(t) =...
  18. Albert1

    MHB Find the Value of $a_{2008}$ in the Sequence

    A sequence as follows : $0,1,-1,2,3,-2,4,5,6,-3,7,8,9,10,-4,11,12,13,14,15,16,-5,--------$ please find :$a_{2008}=?$
  19. Albert1

    MHB What is the value of Angle BAD in a trapezoid with specific conditions?

    A trapezoid ABCD given : (1)$\overline{AB} // \overline{CD}$ (2)$\overline{BC}\ \perp \overline{AC}$ and $\overline{BC}=\overline{AC}$ (3)$\overline{AB}=\overline{BD}$ find the value of $\angle BAD$
  20. S

    What Is the Exact Value of Sin 345.5 Degrees?

    Homework Statement Find the exact value of sin 345.5o Homework Equations Trigonometry Identities The Attempt at a Solution Don't know where to start. Tried sin 345.5o = - sin 14.5o but stuck. Also tried multiply 345.5 with positive integer to get sin 2θ or sin 3θ or sin 4θ but also stuck Thanks
  21. Linder88

    Ordinary differential equation with boundary value condition

    Homework Statement Consider the boundary value problem \begin{equation} u''(t)=-4u+3sin(t),u(0)=1,u(2)=2sin(4)+sin(2)+cos(4) \end{equation} Homework Equations Derive the linear system that arise when discretizating this problem using \begin{equation} u''(t)=\frac{u(t-h)-2u(t)+u(t+h)}{h^2}...
  22. Maria_Porto

    How do I calculate a "medium" jerk value of my motion data?

    I'm a psychologist and I'm currently studying physics but, because this is not my field of study, I'm having great difficulties. I am currently studying biological motion and I have to calculate the jerk of my 2D motion data and I don't even know where to start. My data is basically a bunch of...
  23. S

    Exact Value of Sin 65 Degrees: Trigonometry Identities for Finding the Solution

    Homework Statement Find the exact value of sin 65o Homework Equations Trigonometry Identities The Attempt at a Solution I tried using sin 3x = 3 sin x - 4 sin3x but ended with nasty algebra. sin (3 . 65o) = 3 sin 65 - 4 sin3 65o sin (195o) = 3 sin 65 - 4 sin3 65o sin (180o+15o) = 3 sin 65 -...
  24. G

    How to find exact value of x/2=sinx?

    According to Wolfram it is approx. -1.895 How do I find the exact value of the root though?
  25. R

    MHB So the exact value of Cos(-pi/3) is 1/2.

    Hello! Simple as it sounds, I would greatly appreciate help on finding the exact value of Cos(\frac{-\pi}{3} If I need to find a negative value of Cos, does it become the inverse? So, since if I draw on unit circle, I get (\frac{\sqrt{3}}{2}, \frac{-1}{2}), would the value of Cos(-pi/3) = the...
  26. M

    Expectation value of observable in Bell State

    Homework Statement Consider the bipartite observable O_AB = (sigma_A · n) ⊗ (sigma_B · m) Where n and m are three vectors and sigma_i = (sigma_1_i, sigma_2_i, sigma_3_i) with i = [A,B] are the Pauli vectors. Compute using abstract and matrix representation the expectation value of O_AB...
  27. T

    Linear Differential Equation - Initial Value Problem

    Hello, I'm struggling with a simple problem here. It asks me to solve the following initial value problem: So far I've calculated the integration factor μ(x) = ex-x2 and I multiplied both sides of the equation by it and got this...
  28. R

    Engineering Instantaneous current value in AC circuit

    Homework Statement A sinusoidal supply defined by ## v(t)= 325.27 sin(314.16t+\frac{\pi}{6}) ## is connected across a coil of resistance 25Ω and inductance of 0.5 H. The instantaneous value of the current at 2.968ms is 13.13 mA 21.6 mA 87.8mA 13.8mA Homework Equations ## i(t) = \frac{v(t)}{Z}...
  29. anemone

    MHB What Is the Maximum Value of \(a\) in This Polynomial Inequality?

    Find the greatest value of $a$ for which the inequality $x^4+y^4+z^4+xyz(x+y+z)≥ a(xy+yz+zx)^2$ holds for all values ​​of $x ,\,y$ and $z$.
  30. G

    Friction Coefficient Calculation for Racquet Grip Design

    For my final year project at uni, I am designing a new racquet grip. Past of investigating current products, I am going to test the friction properties of current grips. My plan is to rub a number of grips for a set time and then, using a heat sensor gun, measure the grips heat. My question...
  31. sunrah

    Why is the non-zero value of spatial curvature +/- 1?

    Going from the Newtonian to relativistic version of Friedmann's equation we use the substitution kc^{2} = -\frac{2U}{x^{2}} The derivation considers the equation of motion of a particle with classic Newtonian dynamics. I can sought of see that if space is flat the radius of curvature will be...
  32. M

    Observable System L Matrix, can a value be negative?

    Homework Statement An error matrix is in the form, has a characteristic equation: ## CE: s^2 + 120s + 7200 = 0 ## A state variable feedback system is described by: ## A_F = \begin{bmatrix}0 & 1 \\-616.8 & -40 \end{bmatrix} ## ## B = \begin{bmatrix}0 \\ 1 \end{bmatrix} ## ## C =...
  33. Aristotle

    Initial Value Problem using Laplace Transform help?

    Homework Statement Use laplace transforms to find following initial value problem -- there is no credit for partial fractions. (i assume my teach is against using it..) y'' - 4y' + 3y = 0 ; y(0)=2 y'(0) = 8 Homework Equations Lf'' = ((s^2)*F) - s*f(0) - f'(0) Lf' = sF -...
  34. S

    Range of value to satisfy sufficient and necessary condition

    Homework Statement Let p: x and y satisfy inequality x2 + y2 + 4x - 8y + c < 0 where c is real number q: x and y satisfy x - y + 8 > 0 ; 4x + 3y - 24 < 0 ; y < 0 Find the range of c so that: a. p is sufficient condition for q b. p is necessary condition for q Homework Equations Circle...
  35. L

    Finding distance for a given value between vectors

    Homework Statement Let u = (2,k,1,-4) and v = (3,-1,6,-3) For which values of k is the distance d(u,v) = 6? Homework EquationsThe Attempt at a Solution 6 = √((3-2)2 + (-1-k)2 + (6-1)2 + (-3-4)2) 6 = √(1 + 1 + k2 + 25 + 21) 6 = √(k2 + 48) 36 = k2 + 48 k = √-12 The answers seem to be 6k, -16k...
  36. R

    X0 value for Newton's forward interpolation formula

    If x values are: 10, 20, 30, 40, 50 corresponding y values are:20, 65, 180, 390, 505 then what is y value at x=25. I was having an argument with maths sir. I was saying to take x0 as 10 to get the answer as 107.14, which is correct application of formula, but our maths sir said that we should...
  37. Steve Turchin

    Complex absolute value inequality

    Solve the following inequality. Represent your answer graphically: ## |z-1| + |z-5| < 4 ## Homework Equations ## z = a + bi \\ |x+y| \leq |x| + |y| ## Triangle inequality The Attempt at a Solution ## |z-1| + |z-5| < 4 \\ \\ x = z-1 \ \ , \ \ y = z-5 \\ \\ |z-1+z-5| \leq |z-1| + |z-5| \\...
  38. Mr Davis 97

    Solving Absolute Value Limit: x→2

    Homework Statement Solve: ##\displaystyle \lim_{x\rightarrow 2} \frac{\left | x^2 + 3x + 2 \right |}{x^2 - 4}##. Homework EquationsThe Attempt at a Solution I am trying to solve the following limit: ##\displaystyle \lim_{x\rightarrow 2} \frac{\left | x^2 + 3x + 2 \right |}{x^2 - 4} =...
  39. B

    Determine the value of B and C of a function

    Homework Statement Determine the value of b and c such that the function is continuous on the entire real number line Homework Equations f(x) = { x+1 , 1<x<3 x^2+bx+c, |x-2| >=1 The Attempt at a Solution What is the best way to get the b and c value?[/B]
  40. Calpalned

    Determining the value of a constant

    Example 3 shows the derivation of one of the kinematics equations. I am quite familiar with it. At the part where it says dx/dt = gt + constant, how does one determine if constant = x_0 or v_0? Thank you.
  41. L

    Understanding the Finite Value of ##\zeta(-1)##

    \sum^{\infty}_{n=1}\frac{1}{n^{\alpha}}=\zeta(\alpha) For ##\alpha=-1## ##\zeta(-1)=-\frac{1}{12}## I do not see any difference between sum ##1+2+3+4+5+...## and ##\zeta(-1)##. How the second one is finite and how we get negative result when all numbers which we add are positive. Thanks for...
  42. evinda

    MHB Solver for Value of $a$: Unique, Infinite, No Solution

    Hello! (Wave) I want to find the value of $a$ for which the system $\begin{pmatrix} a & 1 & 1\\ 1 & a & 1\\ 1 & 1 & a \end{pmatrix}\begin{pmatrix} x_1\\ x_2\\ x_3 \end{pmatrix}=\begin{pmatrix} 1\\ 1\\ 1\end{pmatrix}$ has a unique solution has infinite solutions has no solution The...
  43. evinda

    MHB Solving a Boundary Value Problem: Non-Uniform vs. Uniform Partitioning

    Hello! (Wave)Consider the boundary value problem $\left\{\begin{matrix} - \epsilon u''+u'=1 &, x \in [0,1] \\ u(0)=u(1)=0 & \end{matrix}\right.$ where $\epsilon$ is a positive given constant. I have to express a finite difference method for its numerical solution. How can we know whether it...
  44. T

    Calculating Expectation Values for Independent Random Variables

    Homework Statement If X1 has mean -3 and variance 2 while X2 has mean 5 and variance 4 and the two are independent find a) E(X1 - X2) b) Var(X1 - X2)The Attempt at a Solution I am not very clear on what I am supposed to be doing for this problem. I don't fully understand this expectation value...
  45. C

    MHB Using Reimann sum to estimate the value of a double integral

    If R = [−3, 1] × [−2, 0], Use a Riemann sum with m = 4, n = 2 to estimate the value of ∫∫R(y2 − 2x2) dA. Take the sample points to be the upper left corners of the squares. So far, I found the indefinite integral of the function to be y3/3 - 2x3/3 Not sure where to go from here
  46. toboldlygo

    Conditional Statments and Truth Value

    So, I know that P ⊃ Q is a true statement even if P is false as long as Q is true. However, I don't understand why that is, or how that is logically sound. Is it because I'm stuck in thinking of these types of statements as "If P, then Q," and they are not supposed to be thought of that way? How...
  47. moondaaay

    How do I solve absolute value inequalities involving polynomials?

    1. Homework Equations Solving Polynomial Inequalities The Attempt at a Solution Then I used the property of absolute value inequality to get rid of it. But I really don't know if I'm doing the right step. Is this correct? So that I could separate them in two cases and find the...
  48. S

    Solve Initial Value Problem and Determining Interval

    Homework Statement Solve the initial value problem and determine at least approximately where the solution is valid (2x-y) + (2y-x)y' = 0 y(1) = 3 Homework EquationsThe Attempt at a Solution I know how to solve it, and I got the correct answer, which was: 7 = x^2 - yx + y^2 and then applying...
  49. K

    Does pressure change along a vertical path with pressurized fluid at 70psi?

    Hello, I am willing to know if the value of pressurized fluid along a rectangular path placed normal to ground (let's say 2 stories high) would show any change in pressure along the lines normal to ground. I am not worried where fluid would move horizontal to ground but what would happen when it...
  50. S

    MHB Given a range value, find the correspoding domain value

    Here is the problem: If -1 is a range value for the function f(x) = -6x + 11, find the domain value. thank you for your help
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