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gibson:teaching:fall-2016:math753:quadrature [2016/11/17 06:59]
gibson
gibson:teaching:fall-2016:math753:quadrature [2016/11/17 07:04]
gibson
Line 29: Line 29:
 interpolation between triplets of  datapoints. interpolation between triplets of  datapoints.
 \begin{equation*} \begin{equation*}
-\int_a^b f(x) \, dx = \frac{h}{3} \left( y_0 + 4 \sum_{i=1, i \text{odd}}^{N-1} y_i + 2\sum_{i=2, i \text{even}}^{N-2} y_i + y_N\right) - \frac{b-a}{180} h^4 f^{(iv)}(c)+\int_a^b f(x) \, dx = \frac{h}{3} \left( y_0 + 4 \sum_{i=1, i \text{odd}}^{N-1} y_i + 2\sum_{i=2, i \text{even}}^{N-2} y_i + y_N\right) - \frac{b-a}{180} ​\, h^4 \, f^{(iv)}(c)
 \end{equation*} \end{equation*}
 for some $c$ where $a<​c<​b$,​ and where $f^{(iv)}$ is the fourth derivative of $f$. Simpson'​s rule requires that $N$ is even, so that the total number of gridpoints, $N+1$, is odd. for some $c$ where $a<​c<​b$,​ and where $f^{(iv)}$ is the fourth derivative of $f$. Simpson'​s rule requires that $N$ is even, so that the total number of gridpoints, $N+1$, is odd.
  
-For example, for $N=6$ and 7 gridpoints, we have +For example, for $N=6$ and $N+1=7gridpoints, we have 
  
 \begin{equation*} \begin{equation*}
 \int_a^b f(x) \, dx = \frac{h}{3} \left(y_0 + 4y_1 + 2y_2 + 4y_3 + 2y_4  + 4y_5 + y_6 \right) + O(h^4) \int_a^b f(x) \, dx = \frac{h}{3} \left(y_0 + 4y_1 + 2y_2 + 4y_3 + 2y_4  + 4y_5 + y_6 \right) + O(h^4)
 \end{equation*} \end{equation*}
 +
 +
 +=== Further reading ===
 +
 +  * [[https://​en.wikipedia.org/​wiki/​Trapezoidal_rule|Trapezoidal rule]] (wikipedia)
 +  * [[http://​mathworld.wolfram.com/​TrapezoidalRule.html|Trapezoidal rule]] (math world)  ​
 +  * [[https://​en.wikipedia.org/​wiki/​Simpson%27s_rule|Simpson'​s rule]] (wikipedia)
 +  * [[http://​mathworld.wolfram.com/​SimpsonsRule.html|Simpson'​s rule]] (math world)
 +  * [[https://​en.wikipedia.org/​wiki/​Newton%E2%80%93Cotes_formulas|Newton-Cotes formulae]] (wikipedia)
 +  * [[http://​mathworld.wolfram.com/​Newton-CotesFormulas.html|Newton-Cotes formulae]] (math world)
 +  * [[http://​mathworld.wolfram.com/​TrapezoidalRule.html|Trapezoidal rule]] (math world)
gibson/teaching/fall-2016/math753/quadrature.txt ยท Last modified: 2016/11/17 07:04 by gibson