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keynote:lesson11 [2010/06/26 09:27]
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keynote:lesson11 [2010/06/26 09:33]
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      ​$\left\{ {\begin{array}\ {y=sinx,​} ​ \\ {z=-sinx}. ​       \\  \end{array} } \right.$\\      ​$\left\{ {\begin{array}\ {y=sinx,​} ​ \\ {z=-sinx}. ​       \\  \end{array} } \right.$\\
  
-            <​note>​ edited by 谭小球(0921062)2010/​06/​10</​note>​ +            <​note>​ edited by 谭小球(0921062)2010/​06/​10</​note>​\\ 
- ​★例2 求泛函$J[y(x),​z(x)]=\int_{x_0}^{x_1}{F(y',​z'​)}dx,$ 的极值曲线,其中假设 F_{y'​y'​}-F^2_{y'​z'​} ≠0 \\+ ​★例2 求泛函$J[y(x),​z(x)]=\int_{x_0}^{x_1}{F(y',​z'​)dx,​}$ 的极值曲线,其中假设 F_{y'​y'​}-F^2_{y'​z'​} ≠0 \\
 解:因为F_y=F_z=0,​故Euler方程组为 \\ 解:因为F_y=F_z=0,​故Euler方程组为 \\
 $\left\{ {\begin{array}\ {\frac{d}{dx}(F_{y'​})=0,​} ​ \\ {\frac{d}{dx}(F_{z'​})=0}. ​       \\  \end{array} } \right.$\\ $\left\{ {\begin{array}\ {\frac{d}{dx}(F_{y'​})=0,​} ​ \\ {\frac{d}{dx}(F_{z'​})=0}. ​       \\  \end{array} } \right.$\\
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 是所求的极值曲线。\\ 是所求的极值曲线。\\
 ·含n(n>​2)个未知函数的泛函极值的必要条件\\ ·含n(n>​2)个未知函数的泛函极值的必要条件\\
-泛函$J=\int_{x_0}^{x_1}{F(x,​y_1,​y_2,​…,​y_n,​y'​_1,​y'​_2,​…y'​_n)}dx,​$在满足边界条件 \\+泛函$J=\int_{x_0}^{x_1}{F(x,​y_1,​y_2,​…,​y_n,​y'​_1,​y'​_2,​…y'​_n)dx,​}$在满足边界条件 \\
 $\left\{ {\begin{array}\ {y_i(x_0)=y_{i0},​} ​ \\ {y_i(x_1)=y_{i1}},​i=1,​2,​…n, ​       \\  \end{array} } \right.$\\ $\left\{ {\begin{array}\ {y_i(x_0)=y_{i0},​} ​ \\ {y_i(x_1)=y_{i1}},​i=1,​2,​…n, ​       \\  \end{array} } \right.$\\
 下,取得极值的必要条件是y_1(x),​y_2(x),​…,​y_n(x),​满足Euler方程组\\ 下,取得极值的必要条件是y_1(x),​y_2(x),​…,​y_n(x),​满足Euler方程组\\
keynote/lesson11.txt · Last modified: 2023/08/19 21:02 (external edit)