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  2. Limit of a function - Wikipedia

    en.wikipedia.org/wiki/Limit_of_a_function

    Note that defining what it means for a sequence x n to converge to a requires the epsilon, delta method. Similarly as it was the case of Weierstrass's definition, a more general Heine definition applies to functions defined on subsets of the real line. Let f be a real-valued function with the domain Dm(f).

  3. Numerical solution of the convection–diffusion equation

    en.wikipedia.org/wiki/Numerical_solution_of_the...

    This article describes how to use a computer to calculate an approximate numerical solution of the discretized equation, in a time-dependent situation. In order to be concrete, this article focuses on heat flow, an important example where the convection–diffusion equation applies. However, the same mathematical analysis works equally well to ...

  4. Euler method - Wikipedia

    en.wikipedia.org/wiki/Euler_method

    The exact solution of the differential equation is () =, so () =. Although the approximation of the Euler method was not very precise in this specific case, particularly due to a large value step size h {\displaystyle h} , its behaviour is qualitatively correct as the figure shows.

  5. Stability theory - Wikipedia

    en.wikipedia.org/wiki/Stability_theory

    where x(t) ∈ R n and A is an n×n matrix with real entries, has a constant solution = (In a different language, the origin 0 ∈ R n is an equilibrium point of the corresponding dynamical system.) This solution is asymptotically stable as t → ∞ ("in the future") if and only if for all eigenvalues λ of A, Re(λ) < 0.

  6. Dirac delta function - Wikipedia

    en.wikipedia.org/wiki/Dirac_delta_function

    As a result, the nascent delta functions that arise as fundamental solutions of the associated Cauchy problems are generally oscillatory integrals. An example, which comes from a solution of the Euler–Tricomi equation of transonic gas dynamics , [ 61 ] is the rescaled Airy function ε − 1 / 3 Ai ⁡ ( x ε − 1 / 3 ) . {\displaystyle ...

  7. Numerical stability - Wikipedia

    en.wikipedia.org/wiki/Numerical_stability

    Computing the square root of 2 (which is roughly 1.41421) is a well-posed problem.Many algorithms solve this problem by starting with an initial approximation x 0 to , for instance x 0 = 1.4, and then computing improved guesses x 1, x 2, etc.

  8. Delta potential - Wikipedia

    en.wikipedia.org/wiki/Delta_potential

    The delta potential is the potential = (), where δ(x) is the Dirac delta function. It is called a delta potential well if λ is negative, and a delta potential barrier if λ is positive. The delta has been defined to occur at the origin for simplicity; a shift in the delta function's argument does not change any of the following results.

  9. Nonstandard calculus - Wikipedia

    en.wikipedia.org/wiki/Nonstandard_calculus

    Keisler's Elementary Calculus: An Infinitesimal Approach defines continuity on page 125 in terms of infinitesimals, to the exclusion of epsilon, delta methods. The derivative is defined on page 45 using infinitesimals rather than an epsilon-delta approach. The integral is defined on page 183 in terms of infinitesimals.