|
| 1 | +``` |
| 2 | +title: Numerical Analysis |
| 3 | +author: Jishnu |
| 4 | +``` |
| 5 | + |
| 6 | +# Table of Contents |
| 7 | + |
| 8 | +1. [Root Finding Methods](#org770afdb) |
| 9 | + 1. [Newton’s method](#org013f1b7) |
| 10 | + 2. [Fixed point method](#orgde6567b) |
| 11 | + 3. [Secant method](#org4ebbe87) |
| 12 | +2. [Interpolation techniques](#org9e2a72e) |
| 13 | + 1. [Hermite Interpolation](#orgd63ca7f) |
| 14 | + 2. [Lagrange Interpolation](#org1e8da43) |
| 15 | + 3. [Newton’s Interpolation](#orgd4f58aa) |
| 16 | +3. [Integration methods](#org8e7e5c8) |
| 17 | + 1. [Euler Method](#org351da1a) |
| 18 | + 2. [Newton–Cotes Method](#org75020aa) |
| 19 | + 3. [Predictor–Corrector Method](#orgcf8f14e) |
| 20 | + 4. [Trapizoidal method](#orgf561a2c) |
| 21 | + |
| 22 | + |
| 23 | + |
| 24 | +<a id="org770afdb"></a> |
| 25 | + |
| 26 | +# Root Finding Methods |
| 27 | + |
| 28 | + |
| 29 | +<a id="org013f1b7"></a> |
| 30 | + |
| 31 | +## [Newton’s method](https://en.wikipedia.org/wiki/Newton%27s_method) |
| 32 | + |
| 33 | +Newton’s method (also known as the Newton–Raphson method) is a method for finding successively better approximations to the roots (or zeroes) of a real-valued function. The process is repeated as $$ x_{n+1}=x_{n}-{\frac {f(x_{n})}{f'(x_{n})}} $$ |
| 34 | + |
| 35 | + |
| 36 | +<a id="orgde6567b"></a> |
| 37 | + |
| 38 | +## [Fixed point method](https://en.wikipedia.org/wiki/Fixed-point_iteration) |
| 39 | + |
| 40 | +Fixed-point iteration is a method of computing fixed points of iterated functions. More specifically, given a function f defined on the real numbers with real values and given a point x0 in the domain of f, the fixed point iteration is |
| 41 | +$$ x_{n+1}=f(x_{n}),\,n=0,1,2,\dots$$ |
| 42 | + |
| 43 | + |
| 44 | +<a id="org4ebbe87"></a> |
| 45 | + |
| 46 | +## [Secant method](https://en.wikipedia.org/wiki/Secant_method) |
| 47 | + |
| 48 | +Secant method is a root-finding algorithm that uses a succession of roots of secant lines to better approximate a root of a function f. The secant method can be thought of as a finite difference approximation of Newton’s method. |
| 49 | +$$ x_{n}=x_{n-1}-f(x_{n-1}){\frac {x_{n-1}-x_{n-2}}{f(x_{n-1})-f(x_{n-2})}}={\frac {x_{n-2}f(x_{n-1})-x_{n-1}f(x_{n-2})}{f(x_{n-1})-f(x_{n-2})}}. $$ |
| 50 | + |
| 51 | + |
| 52 | +<a id="org9e2a72e"></a> |
| 53 | + |
| 54 | +# Interpolation techniques |
| 55 | + |
| 56 | + |
| 57 | +<a id="orgd63ca7f"></a> |
| 58 | + |
| 59 | +## Hermite Interpolation |
| 60 | + |
| 61 | +Hermite Interpolation is a method of interpolating data points as a polynomial function. The generated Hermite interpolating polynomial is closely related to the Newton polynomial, in that both are derived from the calculation of divided differences. |
| 62 | + |
| 63 | + |
| 64 | +<a id="org1e8da43"></a> |
| 65 | + |
| 66 | +## Lagrange Interpolation |
| 67 | + |
| 68 | +Lagrange polynomials are used for polynomial interpolation. See [Wikipedia](https://en.wikipedia.org/wiki/Lagrange_polynomial) |
| 69 | + |
| 70 | + |
| 71 | +<a id="orgd4f58aa"></a> |
| 72 | + |
| 73 | +## Newton’s Interpolation |
| 74 | + |
| 75 | +Newton’s divided differences is an algorithm, historically used for computing tables of logarithms and trigonometric functions. Divided differences is a recursive division process. The method can be used to calculate the coefficients in the interpolation polynomial in the Newton form. |
| 76 | + |
| 77 | + |
| 78 | +<a id="org8e7e5c8"></a> |
| 79 | + |
| 80 | +# Integration methods |
| 81 | + |
| 82 | + |
| 83 | +<a id="org351da1a"></a> |
| 84 | + |
| 85 | +## Euler Method |
| 86 | + |
| 87 | +Euler method (also called forward Euler method) is a first-order numerical procedure for solving ordinary differential equations (ODEs) with a given initial value. It is the most basic explicit method for numerical integration of ordinary differential equations and is the simplest Runge–Kutta method. |
| 88 | +$$ y_{n+1} = y_{n} + h f(t_{n} , y_{n}) $$ |
| 89 | + |
| 90 | + |
| 91 | +<a id="org75020aa"></a> |
| 92 | + |
| 93 | +## Newton–Cotes Method |
| 94 | + |
| 95 | +Newton–Cotes formulae, also called the Newton–Cotes quadrature rules or simply Newton–Cotes rules, are a group of formulae for numerical integration (also called quadrature) based on evaluating the integrand at equally spaced points. They are named after Isaac Newton and Roger Cotes. |
| 96 | + |
| 97 | + |
| 98 | +<a id="orgcf8f14e"></a> |
| 99 | + |
| 100 | +## Predictor–Corrector Method |
| 101 | + |
| 102 | +Predictor–Corrector methods belong to a class of algorithms designed to integrate ordinary differential equations – to find an unknown function that satisfies a given differential equation. All such algorithms proceed in two steps: |
| 103 | + |
| 104 | +1. The initial, “prediction” step, starts from a function fitted to the function-values and derivative-values at a preceding set of points to extrapolate (“anticipate”) this function’s value at a subsequent, new point. |
| 105 | +2. The next, “corrector” step refines the initial approximation by using the predicted value of the function and another method to interpolate that unknown function’s value at the same subsequent point. |
| 106 | + |
| 107 | + |
| 108 | +<a id="orgf561a2c"></a> |
| 109 | + |
| 110 | +## Trapizoidal method |
| 111 | + |
| 112 | +Trapezoidal rule is a technique for approximating the definite integral. The trapezoidal rule works by approximating the region under the graph of the function f(x) as a trapezoid and calculating its area. |
| 113 | +$$ \int _{a}^{b}f(x)\,dx\approx \sum _{k=1}^{N}{\frac {f(x_{k-1})+f(x_{k})}{2}}\Delta x_{k}$$ |
| 114 | + |
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