VIẾT RA CT LATEX SAU ` \alpha \beta \delta \varepsilon \zeta \theta \eta \vartheta \iota \kappa \mu \lambda \nu \rho \varrho \sigma \Leftarrow \nleftarrow \downarrow \downdownarrows \leftrightarrow \underbrace{abc} \overline{abc} \overbrace{abc} \widehat{abc} \dashleftarrow \prod \iint_{a}^{b} \cosh \arccos \sec \tan \cot \frac{\partial }{\partial x} \Finv \blacklozenge \angle \angle \Box \lozenge \boxtimes \boxminus \blacklozenge \spadesuit \not\equiv \curlyeqprec \sqcup \exists \mp \uplus \because \mathbf{V}_1 \times \mathbf{V}_2 =` `\begin{vmatrix}\mathbf{i} & \mathbf{j} & \mathbf{k} \\\frac{\partial X}{\partial u} & \frac{\partial Y}{\partial u} & 0 \\\frac{\partial X}{\partial v} & \frac{\partial Y}{\partial v} & 0\end{vmatrix} \left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right) \begin{aligned}\nabla \times \vec{\mathbf{B}} -\, \frac1c\, ``\frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \\ \nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\\nabla \cdot \vec{\mathbf{B}} & = 0 \end{aligned} \frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} =1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}}{1+\frac{e^{-8\pi}} {1+\ldots}} } } \frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} =1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}}{1+\frac{e^{-8\pi}} {1+\ldots}} } } `