Scroll Top
19th Ave New York, NY 95822, USA

数学代写|matlab代写|Numerical Integration

如果你也在 怎样代写matlab这个学科遇到相关的难题,请随时右上角联系我们的24/7代写客服。matlab是由MathWorks公司开发的一种专有的多范式编程语言和数字计算环境。MATLAB允许进行矩阵操作、绘制函数和数据、实现算法、创建用户界面以及与用其他语言编写的程序对接。

matlab尽管MATLAB主要用于数值计算,但一个可选的工具箱使用MuPAD符号引擎,允许访问符号计算能力。一个额外的软件包,Simulink,为动态和嵌入式系统增加了图形化的多域仿真和基于模型的设计。截至2020年,MATLAB在全球拥有超过400万用户。他们来自工程、科学和经济的各种背景。

my-assignmentexpert™ matlab作业代写,免费提交作业要求, 满意后付款,成绩80\%以下全额退款,安全省心无顾虑。专业硕 博写手团队,所有订单可靠准时,保证 100% 原创。my-assignmentexpert™, 最高质量的matlab作业代写,服务覆盖北美、欧洲、澳洲等 国家。 在代写价格方面,考虑到同学们的经济条件,在保障代写质量的前提下,我们为客户提供最合理的价格。 由于统计Statistics作业种类很多,同时其中的大部分作业在字数上都没有具体要求,因此matlab作业代写的价格不固定。通常在经济学专家查看完作业要求之后会给出报价。作业难度和截止日期对价格也有很大的影响。

想知道您作业确定的价格吗? 免费下单以相关学科的专家能了解具体的要求之后在1-3个小时就提出价格。专家的 报价比上列的价格能便宜好几倍。

my-assignmentexpert™ 为您的留学生涯保驾护航 在数学Mathematics作业代写方面已经树立了自己的口碑, 保证靠谱, 高质且原创的matlab代写服务。我们的专家在数学Mathematics代写方面经验极为丰富,各种matlab相关的作业也就用不着 说。

我们提供的matlab及其相关学科的代写,服务范围广, 其中包括但不限于:

数学代写|matlab代写|Numerical Integration

数学代写|matlab代写|Introduction

Numerical integration, also known as quadrature, is intrinsically a much more accurate procedure than numerical differentiation. Quadrature approximates the definite integral
$$
\int_{a}^{b} f(x) d x
$$
by the sum
$$
I=\sum_{i=1}^{n} A_{i} f\left(x_{i}\right)
$$
where the nodal abscissas $x_{i}$ and weights $A_{i}$ depend on the particular rule used for the quadrature. All rules of quadrature are derived from polynomial interpolation of the integrand. Therefore, they work best if $f(x)$ can be approximated by a polynomial.
Methods of numerical integration can be divided into two groups: Newton-Cotes formulas and Gaussian quadrature. Newton-Cotes formulas are characterized by equally spaced abscissas, and include well-known methods such as the trapezoidal rule and Simpson’s rule. They are most useful if $f(x)$ has already been computed at equal intervals, or can be computed at low cost. Since Newton-Cotes formulas are based on local interpolation, they require only a piecewise fit to a polynomial.

In Gaussian quadrature the locations of the abscissas are chosen to yield the best possible accuracy. Because Gaussian quadrature requires fewer evaluations of the integrand for a given level of precision, it is popular in cases where $f(x)$ is expensive to evaluate. Another advantage of Gaussian quadrature is its ability to handle integrable singularities, enabling us to evaluate expressions such as
$$
\int_{0}^{1} \frac{g(x)}{\sqrt{1-x^{2}}} d x
$$
provided that $g(x)$ is a well-behaved function.

数学代写|matlab代写|Newton–Cotes Formulas

Consider the definite integral
$$
\int_{a}^{b} f(x) d x
$$
We divide the range of integration $(a, b)$ into $n-1$ equal intervals of length $h=$ $(b-a) /(n-1)$ each, as shown in Fig. 6.1, and denote the abscissas of the resulting nodes by $x_{1}, x_{2}, \ldots, x_{n}$. Next we approximate $f(x)$ by a polynomial of degree $n-1$ that intersects all the nodes. Lagrange’s form of this polynomial, Eq. (3.1a), is
$$
P_{n-1}(x)=\sum_{i=1}^{n} f\left(x_{i}\right) \ell_{i}(x)
$$
where $\ell_{i}(x)$ are the cardinal functions defined in Eq. (3.1b). Therefore, an approximation to the integral in Eq. (6.1) is
$$
I=\int_{a}^{b} P_{n-1}(x) d x=\sum_{i=1}^{n}\left[f\left(x_{i}\right) \int_{a}^{b} \ell_{i}(x) d x\right]=\sum_{i=1}^{n} A_{i} f\left(x_{i}\right)
$$
where
$$
A_{i}=\int_{a}^{b} \ell_{i}(x) d x, \quad i=1,2, \ldots, n
$$
Equations (6.2) are the Newton-Cotes formulas. Classical examples of these formulas are the trapezoidal rule $(n=2)$, Simpson’s rule $(n=3)$ and Simpson’s $3 / 8$ rule $(n=4)$. The most important of these is the trapezoidal rule. It can be combined with Richardson extrapolation into an efficient algorithm known as Romberg integration, which makes the other classical rules somewhat redundant.

数学代写|MATLAB代写|Romberg Integration

Romberg integration combines the composite trapezoidal rule with Richardson extrapolation (see Art. 5.3). Let us first introduce the notation
$$
R_{i, 1}=I_{i}
$$
where, as before, $I_{i}$ represents the approximate value of $\int_{a}^{b} f(x) d x$ computed by the recursive trapezoidal rule using $2^{i-1}$ panels. Recall that the error in this approximation is $E=c_{1} h^{2}+c_{2} h^{4}+\cdots$, where
$$
h=\frac{b-a}{2^{i-1}}
$$
is the width of a panel.
Romberg integration starts with the computation of $R_{1,1}=I_{1}$ (one panel) and $R_{2,1}=I_{2}$ (two panels) from the trapezoidal rule. The leading error term $c_{1} h^{2}$ is then eliminated by Richardson extrapolation. Using $p=2$ (the exponent in the error term) in Eq. (5.9) and denoting the result by $R_{2,2}$, we obtain
$$
R_{2,2}=\frac{2^{2} R_{2,1}-R_{1,1}}{2^{2}-1}=\frac{4}{3} R_{2,1}-\frac{1}{3} R_{1,1}
$$
It is convenient to store the results in an array of the form
$$
\left[\begin{array}{ll}
R_{1,1} & \
R_{2,1} & R_{2,2}
\end{array}\right]
$$
The next step is to calculate $R_{3,1}=I_{3}$ (four panels) and repeat Richardson extrapolation with $R_{2,1}$ and $R_{3,1}$, storing the result as $R_{3,2}$ :
$$
R_{3,2}=\frac{4}{3} R_{3,1}-\frac{1}{3} R_{2,1}
$$
The elements of array $\mathbf{R}$ calculated so far are
$$
\left[\begin{array}{ll}
R_{1,1} & \
R_{2,1} & R_{2,2} \
R_{3,1} & R_{3,2}
\end{array}\right]
$$
Both elements of the second column have an error of the form $c_{2} h^{4}$, which can also be eliminated with Richardson extrapolation. Using $p=4$ in Eq. (5.9), we get
$$
R_{3,3}=\frac{2^{4} R_{3,2}-R_{2,2}}{2^{4}-1}=\frac{16}{15} R_{3,2}-\frac{1}{15} R_{2,2}
$$
This result has an error of $\mathcal{O}\left(h^{6}\right)$. The array has now expanded to
$$
\left[\begin{array}{lll}
R_{1,1} & & \
R_{2,1} & R_{2,2} & \
R_{3,1} & R_{3,2} & R_{3,3}
\end{array}\right]
$$

数学代写|matlab代写|Numerical Integration

matlab代写

数学代写|MATLAB代写|INTRODUCTION

数值积分,也称为求积,本质上是比数值微分更准确的过程。求积逼近定积分
∫一种bF(X)dX
按总和
一世=∑一世=1n一种一世F(X一世)
节点横坐标在哪里X一世和权重一种一世取决于用于求积的特定规则。所有的求积规则都是从被积函数的多项式插值推导出来的。因此,如果F(X)可以用多项式来近似。
数值积分的方法可以分为两组:Newton-Cotes 公式和 Gaussian 求积。Newton-Cotes 公式以等距横坐标为特征,包括梯形法则和辛普森法则等众所周知的方法。它们是最有用的,如果F(X)已经以相等的间隔计算,或者可以以低成本计算。由于 Newton-Cotes 公式基于局部插值,因此它们只需要对多项式进行分段拟合。

在高斯求积中,选择横坐标的位置以产生可能的最佳精度。因为高斯求积对于给定的精度水平需要较少的被积函数评估,所以它在以下情况下很受欢迎F(X)评估是昂贵的。高斯求积的另一个优点是它能够处理可积奇点,使我们能够评估表达式,例如
∫01G(X)1−X2dX
前提是G(X)是一个表现良好的函数。

数学代写|MATLAB代写|NEWTON–COTES FORMULAS

考虑定积分
∫一种bF(X)dX
我们划分集成范围(一种,b)进入n−1等长间隔H= (b−一种)/(n−1)每个,如图 6.1 所示,并表示结果节点的横坐标为X1,X2,…,Xn. 接下来我们近似F(X)由多项式n−1与所有节点相交。这个多项式的拉格朗日形式,方程式。3.1一种, 是
磷n−1(X)=∑一世=1nF(X一世)ℓ一世(X)
在哪里ℓ一世(X)是方程式中定义的基数函数。3.1b. 因此,方程中积分的近似值。6.1是
一世=∫一种b磷n−1(X)dX=∑一世=1n[F(X一世)∫一种bℓ一世(X)dX]=∑一世=1n一种一世F(X一世)
在哪里
一种一世=∫一种bℓ一世(X)dX,一世=1,2,…,n
方程6.2是牛顿-科茨公式。这些公式的经典例子是梯形规则(n=2), 辛普森法则(n=3)和辛普森的3/8规则(n=4). 其中最重要的是梯形规则。它可以与 Richardson 外推法相结合,形成一种称为 Romberg 积分的有效算法,这使得其他经典规则有些多余。

数学代写|MATLAB代写|ROMBERG INTEGRATION

Romberg 积分将复合梯形规则与 Richardson 外推相结合s和和一种r吨.5.3. 我们先介绍一下符号
R一世,1=一世一世
和以前一样,一世一世表示的近似值∫一种bF(X)dX使用递归梯形规则计算2一世−1面板。回想一下,这个近似值的误差是和=C1H2+C2H4+⋯, 在哪里
H=b−一种2一世−1
是面板的宽度。
Romberg 积分从计算R1,1=一世1 这n和p一种n和l和R2,1=一世2 吨在这p一种n和ls从梯形法则。主要误差项C1H2然后通过理查森外推消除。使用p=2 吨H和和Xp这n和n吨一世n吨H和和rr这r吨和r米在等式。5.9并将结果表示为R2,2, 我们获得
R2,2=22R2,1−R1,122−1=43R2,1−13R1,1
将结果存储在表单的数组中很方便
[R1,1 R2,1R2,2]
下一步是计算R3,1=一世3 F这在rp一种n和ls并重复理查森外推R2,1和R3,1,将结果存储为R3,2 :
R3,2=43R3,1−13R2,1
数组的元素R到目前为止计算的是
[R1,1 R2,1R2,2 R3,1R3,2]
第二列的两个元素都有格式错误C2H4,也可以通过理查森外推法消除。使用p=4在等式。5.9,我们得到
R3,3=24R3,2−R2,224−1=1615R3,2−115R2,2
这个结果有一个错误这(H6). 该数组现已扩展到
[R1,1 R2,1R2,2 R3,1R3,2R3,3]

数学代写|matlab代写

数学代写|matlab代写 请认准UprivateTA™. UprivateTA™为您的留学生涯保驾护航。

抽象代数Galois理论代写

偏微分方程代写成功案例

代数数论代考

概率论代考

离散数学代写

集合论数理逻辑代写案例

时间序列分析代写

离散数学网课代修

Related Posts

Leave a comment