% % polarformel.tex % % (c) 2021 Prod Dr Andreas Müller, OST Ostschweizer Fachhochschule % \bgroup \definecolor{darkcolor}{rgb}{0,0.6,0} \def\yone{-2.1} \def\ytwo{-3.55} \def\ythree{-5.0} \begin{frame}[t] \setlength{\abovedisplayskip}{5pt} \setlength{\belowdisplayskip}{5pt} \frametitle{Polarformel} \vspace{-5pt} \begin{block}{Aufgabe} $\langle x,y\rangle$ aus Werten von $\|\cdot\|_2$ rekonstruieren: \end{block} \begin{center} \begin{tikzpicture}[>=latex,thick] \node at (0,0) {$ \begin{aligned} \uncover<2->{ \|x+ty\|_2^2 &= \|x\|_2^2 +t\langle x,y\rangle +\overline{t}\langle y,x\rangle + \|y\|_2^2} \\ \uncover<3->{ &= \|x\|_2^2 +t\langle x,y\rangle +\overline{t\langle x,y\rangle} + \|y\|_2^2} \\ \uncover<4->{ &= \|x\|_2^2 +2\operatorname{Re}(t\langle x,y\rangle) + \|y\|_2^2} \end{aligned}$}; \uncover<5->{ \draw[->] (-1,-0.9) -- (-3.3,{\yone+0.25}); \node at (-3.5,\yone) {$ \|x\pm y\|_2^2 = \|x\|_2^2 \pm2\operatorname{Re}\langle x,y\rangle + \|y\|_2^2 $}; } \uncover<8->{ \draw[->] (1,-0.9) -- (3.3,{\yone+0.25}); \node at (3.5,\yone) {$ \|x\pm iy\|_2^2 = \|x\|_2^2 \pm2i\operatorname{Im}\langle x,y\rangle + \|y\|_2^2 $}; } \uncover<6->{ \draw[->] (-3.5,{\yone-0.2}) -- (-3.5,{\ytwo+0.2}); \node at (-3.5,\ytwo) {$\operatorname{Re}\langle x,y\rangle = \frac12\bigl( \|x+y\|_2^2-\|x-y\|_2^2 \bigr) $}; } \uncover<9->{ \draw[->] (3.5,{\yone-0.2}) -- (3.5,{\ytwo+0.2}); \node at (3.5,\ytwo) {$ \operatorname{Im}\langle x,y\rangle = \frac1{2i}\bigl( \|x+iy\|_2^2-\|x-iy\|_2^2 \bigr) $}; } \uncover<7->{ \draw[->] (-3.3,{\ytwo-0.25}) -- (-1.5,{\ythree+0.25}); \node at (0,\ythree) {$ \langle x,y\rangle = \frac12\bigl( \|x+y\|_2^2-\|x-y\|_2^2 \uncover<10->{ + \|x+iy\|_2^2-\|x-iy\|_2^2 } \bigr)$}; } \uncover<10->{ \draw[->] (3.3,{\ytwo-0.25}) -- (1.5,{\ythree+0.25}); } \end{tikzpicture} \end{center} \end{frame} \egroup