Commit cf62417e authored by Claude Meny's avatar Claude Meny

Update cheatsheet.fr.md

parent b26df1e7
Pipeline #13301 canceled with stage
...@@ -433,9 +433,9 @@ $`\mathbf{d\phi=\left.\dfrac{\partial \phi}{\partial \alpha}\right|_M\cdot dl_{\ ...@@ -433,9 +433,9 @@ $`\mathbf{d\phi=\left.\dfrac{\partial \phi}{\partial \alpha}\right|_M\cdot dl_{\
La comparaison terme à terme de ces deux expressions de $'d\phi`$ donne : La comparaison terme à terme de ces deux expressions de $'d\phi`$ donne :
$`X_{\alpha}=\dfrac{\partial \phi}{\partial \alpha}\,\dfrac{\partial \alpha}{\partial dl_{\alpha}}`$ , $`X_{\alpha}=\dfrac{\partial \phi}{\partial \alpha}\,\dfrac{\partial \alpha}{\partial dl_{\alpha}}\quad`$,
$`X_{\beta}=\dfrac{\partial \phi}{\partial \beta}\,\dfrac{\partial \beta}{\partial dl_{\beta}}`$ , $`\quad X_{\beta}=\dfrac{\partial \phi}{\partial \beta}\,\dfrac{\partial \beta}{\partial dl_{\beta}}\quad`$,
$`X_{\alpha}=\dfrac{\partial \phi}{\partial \gamma}\,\dfrac{\partial \gamma}{\partial dl_{\gamma}}`$ $`\quad X_{\alpha}=\dfrac{\partial \phi}{\partial \gamma}\,\dfrac{\partial \gamma}{\partial dl_{\gamma}}`$
Soit Soit
...@@ -446,28 +446,23 @@ $`\color{brown}{\mathbf{ ...@@ -446,28 +446,23 @@ $`\color{brown}{\mathbf{
+\dfrac{\partial \gamma}{\partial dl_{\gamma}}\,\dfrac{\partial \phi}{\partial \gamma}\,\overrightarrow{e_{\gamma}} +\dfrac{\partial \gamma}{\partial dl_{\gamma}}\,\dfrac{\partial \phi}{\partial \gamma}\,\overrightarrow{e_{\gamma}}
}}`$ }}`$
##### Expression du gradient en coordonnées cartésiennes
$`\left.\begin{align}
dl_x=dx \Longrightarrow $`\dfrac{\partial x}{\partial dl_{x}}=1\\
dl_y=dy \Longrightarrow $`\dfrac{\partial y}{\partial dl_{y}}=1\\
dl_z=dz \Longrightarrow $`\dfrac{\partial z}{\partial dl_{z}}=1\\
\end{align}\right\}`$
$`\Longrightarrow\color{brown}{\mathbf{\overrightarrow{grad}\,\phi=
\dfrac{\partial \phi}{\partial x}\,\overrightarrow{e_x}
+\dfrac{\partial \phi}{\partial y}\,\overrightarrow{e_y}
+\dfrac{\partial \phi}{\partial z}\,\overrightarrow{e_z}
}}`$
* $`dl_x=dx \Longrightarrow $`\dfrac{\partial x}{\partial dl_{x}}=1`$
À ces coordonnées je peux associer les vecteurs géométriques unitaires * $`dl_y=dy \Longrightarrow $`\dfrac{\partial y}{\partial dl_{y}}=1`$
* $`dl_z=dz \Longrightarrow $`\dfrac{\partial z}{\partial dl_{z}}=1`$
définie
si d'un point quelconque $`M`$ dans l'espace, de coordonnées $`(\alpha_M\,,\beta_M\,,\gamma_M)`$
je fais un déplacement correspondants aux variations de coordonnées $`d\alpha, d\beta \text{ et } d\gamma`$,
$`dV=\left.\dfrac{\partial V}{\partial \alpha}\right|_M\cdot dl_{\alpha} + \left.\dfrac{\partial V}{\partial \beta}\right|_M\cdot dl_{\beta} + \left.\dfrac{\partial V}{\partial \gamma}\right|_M\cdot dl_{\gamma}`$
$`dV=\left.\dfrac{\partial V}{\partial x}\right|_M\cdot dl_x + \left.\dfrac{\partial V}{\partial y}\right|_M\cdot dl_y + \left.\dfrac{\partial V}{\partial z}\right|_M\cdot dl_z`$
##### Expression du gradient en coordonnées cartésiennes
##### Expression du gradient en coordonnées cylindriques ##### Expression du gradient en coordonnées cylindriques
......
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