What is Delta: Definition and 1000 Discussions

A river delta is a landform created by deposition of sediment that is carried by a river as the flow leaves its mouth and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot carry away the supplied sediment. The size and shape of a delta is controlled by the balance between watershed processes that supply sediment, and receiving basin processes that redistribute, sequester, and export that sediment. The size, geometry, and location of the receiving basin also plays an important role in delta evolution. River deltas are important in human civilization, as they are major agricultural production centers and population centers. They can provide coastline defense and can impact drinking water supply. They are also ecologically important, with different species' assemblages depending on their landscape position.

View More On Wikipedia.org
Recent contents Top users
  1. Q

    I am confusing about the delta G(free-energy change). Could any one

    I am confusing about the delta G(free-energy change). Could anyone explain me more about the sign of delta G. wat the exergonic and endergonic process mean? also, wat is the relation between the delta G and delta S(entropy)? I know the formula between them, but I don't quite understand Thank you,
  2. A

    Understanding the Dirac Delta Potential: Exploring Its Integral Properties

    why in the problem of dirac delta potential, the integral \int^{\epsilon}_{-\epsilon}\phi''(x)dx is equal to \phi'(\epsilon)-\phi'(-\epsilon)? but \int^{\epsilon}_{-\epsilon}\phi(x)dx is equal to 0 if, for example\phi(x)=e^x then \phi(x)''=\phi(x) but, the firts integral is...
  3. G

    What is the Difference Between Delta and Differential in Calculus?

    Hi guys Can anybody help me? What is the difference between a delta \delta W and a differential dW? (W a scalar function, for example.) In other words, when shold be used a delta and when a differential? Thanks.
  4. A

    Integrating Delta Functions: The Result

    the integral \int_{-\infty}^{\infty} \! f(t)*\delta (t-t_0) * \delta (w-w(t)) \, dt is?? can be \delta (w-w(t)) * f(t_0) ?
  5. R

    Integrating over a delta function

    Hello, I have just integrated over one variable, x and have now got a delta function \delta(m) where m = constant * (s-s') now I have to integrate over either s or s' but I am a bit confused since if I integrate over say s then the delta function depends on s. Hope I have explained clearly...
  6. V

    Dirac delta function evaluation

    I do not know how to execute the problem with the 2x in the problem. Evaluate the integral: \int_{-4}^{4} (x^2+2x+1) \delta(2x) dx
  7. L

    Young's modulus - calculating delta L

    1. Consider a steel guitar string of initial length L=1.00 meter and cross-sectional area A=0.500 square millimeters. The Young's modulus of the steel is Y=2.0 \times 10^{11} pascals. How far ( Delta L) would such a string stretch under a tension of 1500 Newtons? Use two significant figures in...
  8. E

    Proving the Limit of f(ax) with Delta Epsilon

    hey if lim (x-->0) f(x) = L where 0 < |x| < d1 implies |f(x) - L | < e how do i prove lim (x --> 0) f(ax) = L? i know 0 < |ax| < |a|d1 d2 = |a|d1 but the textbook says d2 = d1/|a| help you guyssssssssssssssssssssssssssssssss
  9. Q

    2D delta function fourier transform

    Homework Statement Given f(x,y) = DeltaFunction(y - x*tan(theta)) a) Plot function. b) Take Fourier transform. c) Plot resulting transform. Homework Equations Delta function condition non-zero condition DeltaFunction(0) = Infinity Sifting property of delta functions The...
  10. Ƒ

    Epsilon-Delta Limits: Finding the Optimal Delta for a Given Epsilon Value

    Given: limit of (sin x)/x as x --> 0 and that ε = .01 Problem: Find the greatest c such that δ between zero and c is good. Give an approximation to three decimal places. Equations: 0 < |x - a| < δ 0 < |f(x) - L| < εAttempt: 0 < |x - 0| < δ 0 < | sin(x)/x - 1| < ε 0 < | sin(x)/x - 1| < .01 0...
  11. K

    A seeming contrdiction in deriving wave function for delta function potential

    First of all, let me copy the standard solution from Griffiths, section 2.5, just for the sake of clarity. PotentialV(x) = - \alpha \delta (x) The bound state eigenfunction: \psi (x) = \left\{ \begin{array}{l} B{e^{\kappa x}}{\rm{ (}}x \le 0{\rm{)}} \\ B{e^{ - \kappa x}}{\rm{...
  12. Ƒ

    What is the Optimal Delta for a Given Epsilon and Limit?

    Given the limit of \frac{x^2+2x}{x^2-3x} as x approaches 0 equals \frac{-2}{3} and that ε = .01, find the greatest c such that every δ between zero and c is good. Give an exact answer. 0 < |x-0| < δ 0 < |\frac{x^2+2x}{|x^2-3x} + \frac{2}{3|}| < ε |\frac{x(x+2)}{|x(x-3)} +...
  13. D

    Confusion with Delta Dirac Function's First Property: Why Does Infinity Equal 1?

    I had just reviewed back the properties of Delta Dirac Function, however I'm having a little confusing about the first property as stated : \delta\left(x-a)\right = 0 if x \neq a, \delta\left(x-a)\right = \infty if x = a;Here is my problem : when integrate over the entire region (ranging from...
  14. Z

    How to Use Epsilon-Delta Definition of Limits to Prove Inequality?

    Homework Statement Let f: \Re \rightarrow \Re and g: \Re \rightarrow \Re be functions such that lim_{x \rightarrow 1} f(x)=\alpha and lim_{x \rightarrow 1} g(x)=\beta for some \alpha, \beta \in \Re with \alpha < \beta . Use the \epsilon-\delta definition of a limit to prove...
  15. H

    Integral of Exp(I x) and the Dirac Delta

    I am trying to see why exactly the momentum eignenstates for a free particle are orthogonal. Simply enough, one gets: \int_{-\infty}^{\infty} e^{i (k-k_0) x} dx = \delta(k-k0) I can see why, if k=k0, this integral goes to zero. But if they differ, I don't see why it goes to zero. You have...
  16. R

    What is the treatment of a delta function potential in charge integration?

    I am trying to integrate a charge density over a volume in order to obtain a total charge, but there is a delta function involved and I am not entirely sure how to treat it. \rho = q* \delta (\textbf{r})- \frac {q\mu^{2} Exp(- \mu r)} {4 \pi r} Q = \int \rho (\textbf{r})d^{3}r...
  17. H

    Help Doing an Epsilon Delta Proof

    Homework Statement given a function defined by f(x,y) {= |xy|^a /(x^2+y^2-xy), if (x,y) cannot be (0,0) and = 0, if (x,y) = (0,0) Find all values of the real number a such that f is continuous everywhere e= epsilon d= delta In order to prove this, I know I need to do an...
  18. J

    Charge Densities & Dirac's Delta Function

    Homework Statement What is the (volume) charge density of a ring of radius r_0 and uniform charge density \lambda? Homework Equations The Dirac Delta Function The Attempt at a Solution I've done a few line charge densities of straight wires along an axis (usually z, but on x as...
  19. S

    Simplifying the integral of dirac delta functions

    hello all, i am unaware of how to handle a delta function. from what i read online the integral will be 1 from one point to another since at zero the "function" is infinite. overall though i don't think i know the material well enough to trust my answer. and help on how to take the integral of...
  20. E

    How do I convert f(x) into its Fourier Transform?

    Homework Statement I am really confused in my electrodynamics class. I have the following function. f(x) = \delta (x + \alpha ) + \delta(x -\alpha) How do i convert this into Fourier Tranform ? Those are dirac delta functions on either sides of the origin. Homework Equations...
  21. H

    Understanding Dirac Delta Squares: Clarifying Doubts

    hi, may someone help me to clarify my doubts... in my work, i encounter diracdelta square \delta(x-x_1)\delta(x-x_2) i am not sure what it means... it seems if i integrate it \int dx \;\delta(x-x_1)\delta(x-x_2) = \delta(x_1-x_2) is either zero of infinity. is this correct? thanks
  22. J

    Calculating Magnetic Splitting: delta E and Visible Lines

    For a field of 15 T, I calculated the magnitude of the splitting, which was 1.391E-22 J (this is delta E), i.e. delta E = |e| / 2m hbar B_z (m2 - m1) where m2 and m1 are the m_l levels. In order to determine the spacings for the visible lines on the absorption spectra, will that just be...
  23. Z

    Finding the Optimal Value of Delta for Convergence in a Quadratic Function

    Homework Statement Suppose f(x) = x2 + x + 1, a = 1, and L = 3. Find a value d > 0 such that 0 < |x - a| < d implies |f(x) - L| < 1/100 Homework Equations The Attempt at a Solution Given 0<|x-1|<d implies 0<|x2 + x + 1 - 3|<1/100 0< x2 + x + -2 <1/100 0<(x+2)(x-1)<1/100 Assume 0<|x-1|<1...
  24. Z

    Proving the limit (epsilon delta) #3

    Homework Statement Prove the following states directly using the formal e, d definition \lim_{x\rightarrow 8} \sqrt{x + 1} = 3 Homework Equations The Attempt at a Solution If 0 < |x-8| < d Then 0 < sqrt((x+1) - 3) < e Let e be given 3 < sqrt(x+1) < e + 3 9 < x + 1 <...
  25. I

    Square root of Dirac Delta function

    Homework Statement I wonder how to deal with the square root of Dirac Delta function, \sqrt{\delta(x)}. Actually, this comes from a problem which asking readers to calculate the wave function of a free particle and of a harmonic oscillator at time t, provided that the wave function at time...
  26. O

    Impulsive delta v hyperbolic and elliptical orbit

    Homework Statement On July 1, 2004, the Cassini spacecraft approached Saturn with hyperbolic excess velocity 5.5 km/s to swing by the planet at the closest approach distance rp = 80,680 km. Compute the impulsive ΔV required for a maneuver performed at the closest approach to Saturn to...
  27. H

    Average Velocity vs. Delta Velocity

    Whats the difference between average velocity and delta velocity? I understand the formulas (ie. Vave = delta displacement/delta time) but I don't understand why you would use one over the other and what the difference is. Thanks for the help.
  28. B

    Spivak calculus ch.5 #24 delta epsilon proof for limit of peicewise function

    Homework Statement Suppose A_n is, for all natural numbers n, some finite set of numbers in [0,1] and A_n intersect A_m={ } if m!=n Define f as follows: f(x) = 1/n if x is in A_n and 0 if x is not in A_n for all n. Prove that the limit as x goes to a of f(x) = 0 for all a in [0,1]...
  29. R

    How to apply the definition of the derivative of a delta function

    I am supposed to prove that δ'(ax) = (1/a)*(1/|a|)*δ'(x) but I cannot figure out where the (1/a) term comes from. Using the scaling theorem I know that δ(ax) = (1/|a|)*δ(x), but how does this apply to the first derivative and does it explain where the (1/a) comes from?
  30. R

    Proof of the derivative of delta function

    The problem is to prove that δ'(ax) = (1/a)*(1/a)*δ'(x), where a is a constant. I tried applying the scaling theorem with the formal definition of δ'(x) but I can not get the second (1/a) term. Does anyone have some insight on this problem? Thank you...
  31. Monocerotis

    Boeing Boeing Delta 4-Heavy: Awesome Vantage Point

    Awesome vantage point.
  32. F

    Why does the following function equate to a delta in classical feild theory

    Homework Statement Can anyone remember a decent argument/derivation for the following representation of the delta function. Homework Equations $ \nabla^2 \frac{1}{|r|} =\delta(r)$ (probally up to some multipicative constant $\frac{1}{2\pi}$ or something The Attempt at a...
  33. A

    Line of charge as a volume charge dist. (w/ Dirac delta fcn.)

    How would you write an infinite line charge with constant charge per unit length \lambda as a volume charge density using Dirac delta functions? Perhaps in cylindrical coordinates? I'm confused because if you integrate this charge distribution over all space, you should get an infinite amount...
  34. L

    How Do You Solve the Symmetric Delta Potential Problem in Quantum Mechanics?

    This problem is a symmetric delta potential problem that I was given a few days ago and I can't seem to get the gist of it. Question: Find the spectrum and wave functions of a particle in the potential V(x)=G[d(x-a)+d(x-a)] Calculate the transmission and reflection amplitude. Where G can be...
  35. Z

    Can a distribution or delta function solve a NONlinear ODE or PDE

    the question is , can a delta function /distribution \delta (x-a) solve a NOnlinear problem of the form F(y,y',y'',x) the question is that in many cases you can NOT multiply a distribution by itself so you could not deal with Nonlinear terms such as (y)^{3} or yy'
  36. S

    How can I find the value of delta when solving for a limit equation?

    Find the value of delta that corresponds to 0.75. Give your value of delta where delta or any positive number will satisfy the conditions . give the answer correct to 3 decimal places, round down if necessary. lim (4+x-3x^3)=2 x-->1
  37. L

    Calculating the Delta of a Function with Zeros

    I need to show that: \delta(g(x)) = \sum_k \frac{\delta(x-x_k)}{|g'(x_k)|} where the set {x_k} are the zeros of g(x) and g'(x_k) \neq 0 I'm not really sure where to start for this problem, any clues would be much appreciated!
  38. Saladsamurai

    What is the Algebraic Method for Finding Delta?

    Given f(x) = x2, L = 4, xo = -2, e = 0.5 find delta. -0.5 < x2 - 4 < 0.5 3.5 < x2 < 4.5 (3.5)1/2 - (-2) < x - (-2) < (4.5)1/2 - (-2) =>|x - xo| < (3.5)1/2 - (-2) ~ 3.87 My text says the answer is 0.12 ? I was convinced that I have been doing these right. Am I?
  39. S

    Dirac delta and divergence

    I know that this question was posted before but I just couldn't get it using another way around. So your comments are highly appreciated. In the textbook, \nabla\bullet\left(\widehat{r}/r^{2}\right)=4\pi\delta^{3}\left(r\right). But when I want to calculate the divergence using Catesian...
  40. J

    Conjecturing the Limit and Finding Delta for Sinusoidal Function

    Let f(X)=\frac{\sin(2x)}{x} and use a graphing utility to conjecture the value of L = \lim_{x->0}f(x) \mbox{ then let } \epsilon =.1 and use the graphing utility and its trace feature to find a positive number \delta such that |f(x)-l|< \epsilon \mbox{ if } 0 < |x| < \delta . My...
  41. Saladsamurai

    Finding Delta Algebraically Thomas' Calculus

    Homework Statement This is Example 5 in Chapter 2.3 of the above mentioned text: Problem: Prove that the \lim_{x\rightarrow2}f(x)=4 if f(x)= x^2 \text{ for }x\ne2\text{ and }f(x)=1\text{ for }x=2 Solution Step 1 Solve the inequality |f(x)-4|<\epsilon to find an open interval...
  42. tony873004

    Einstein Summation Convention, Levi-Civita, and Kronecker delta

    Homework Statement Evaluate the following sums, implied according to the Einstein Summation Convention. \begin{array}{l} \delta _{ii} = \\ \varepsilon _{12j} \delta _{j3} = \\ \varepsilon _{12k} \delta _{1k} = \\ \varepsilon _{1jj} = \\ \end{array} The Attempt at a...
  43. J

    Limits, find delta given epsilon

    A positive number epsilon (e) and a limit L of a function f at a are given. Find delta such that |f(x)-L|< epsilon if 0 < |x-a| < delta. \lim_{x->5}, 1/x= 1/5, \epsilon=.05. That implies the following |\frac{1}{x}-\frac{1}{5}|< \epsilon \mbox{ if }|x-5|<\delta. Which implies...
  44. J

    Calculating Work Done by a Gas on a p-V Diagram

    45. A gas sample expands from Vo to 4.0Vo while its pressure decreases from po to po/4.0. If Vo = 1.0m^3 and po = 40 Pa, how much work is done by the gas if its pressure changes with volume via (a) path A, (b) path B, and (c) path C? The p-V diagram can be found at the following addrs on...
  45. J

    Find delta given epsilon limits

    I have started studying maths on my own using a University maths book that may not lend itself to self study. So I was hoping someone could help me with the following.abs{sqrt{x}-2} < .05 if 0 < abs{x-4} < delta. I rewrite this as abs{sqrt{x}-2} < .05 if abs{(sqrt{x}+2)(sqrt{x}-2)} < delta...
  46. B

    How do you know what delta to choose

    Find the delta for the given epsilon. lim (1/x) =1 epsilon=.07 x->1 Homework Equations The Attempt at a Solution I got to here .07526 >x-1> -.06542 so what one is me delta??
  47. A

    Dirac delta function is continuous and differential

    since dirac delta function is not a literally a function but a limit of function,does it mean that dirac delta function is continuous and differentiable through out the infinity? is there any example of dirac delta function if yes then give meeeeeeee?
  48. J

    Epsilon delta to prove continuity

    I have an example bit I can't quite follow it...? Use epsilon -delta definition of continuity to prove f(x) = 3x^2 - x is continuous at x=2 Ep > 0 and delta > 0 in terms of Ep f(x) -f(2) = 3x^2 - x -(3*2^2 -2) f(x) - f(2) = 3x^2 -x - 10 f(x) - f(2) = (3x + 5)(x - 2) So far so...
  49. W

    Curve Fitting Analysis: Finding Uncertainty in Delta I

    Homework Statement I had to do a curve fit on some data and got an equation to the form:Homework Equations F(t) = a_0 + a_1 t + a_2 t^2The Attempt at a Solution Each parameter has an associated uncertainty. I need to integrate F(t) over a range to get I. How do I find the the uncertainty in...
  50. P

    Mutlivariable Epsilon Delta Proofs

    Like many people on this forum, i am seemingly having a lot of trouble grasping the concepts of Epsilon Delta proofs and the logic behind them. I have read the definition and i realize for e>0 there is a d>0 such that... 0<sqrt((x-1)^2 - (y-b)^2) < d then f(x,y) - L <e (excuse my use of...
Back
Top