Fizik Problem Dergisi



Euler ve de Moivre Formüllerinin Sonuçları

Sedat Han

FPD 1-1(2025), Sayfa [1-9]

Elektronik yayın tarihi: 28 Ekim 2025

Problemler:

Euler ve de Moivre formüllerini kullanılarak aşağıdaki denklemleri çıkarın:

\[\begin{equation}\label{1.1}\tag{1.1} \cos x=\frac{e^{ix}+e^{-ix}}{2}, \end{equation}\]

\[\begin{equation}\label{1.2}\tag{1.2} \sin x=\frac{e^{ix}-e^{-ix}}{2i}, \end{equation}\]

\[\begin{equation}\label{1.3}\tag{1.3} \sin^2x+\cos^2x=1, \end{equation}\]

\[\begin{equation}\label{1.4}\tag{1.4} \sin(\alpha+\beta)=\sin\alpha\cos\beta+\cos\alpha\sin\beta, \end{equation}\]

\[\begin{equation}\label{1.5}\tag{1.5} \sin(\alpha-\beta)=\sin\alpha\cos\beta-\cos\alpha\sin\beta, \end{equation}\]

\[\begin{equation}\label{1.6}\tag{1.6} \cos(\alpha+\beta)=\cos\alpha\cos\beta-\sin\alpha\sin\beta, \end{equation}\]

\[\begin{equation}\label{1.7}\tag{1.7} \cos(\alpha-\beta)=\cos\alpha\cos\beta+\sin\alpha\sin\beta, \end{equation}\]

\[\begin{equation}\label{1.8}\tag{1.8} \tan(\alpha+\beta)=\frac{\tan\alpha+\tan\beta}{1-\tan\alpha\tan\beta}, \end{equation}\]

\[\begin{equation}\label{1.9}\tag{1.9} \sin 2\alpha=2\sin\alpha\cos\alpha, \end{equation}\]

\[\begin{equation}\label{1.10}\tag{1.10} \cos 2\alpha=\cos^2\alpha-\sin^2\alpha, \end{equation}\]

\[\begin{equation}\label{1.11}\tag{1.11} \cos 2\alpha=2\cos^2\alpha-1, \end{equation}\]

\[\begin{equation}\label{1.12}\tag{1.12} \cos^2\alpha=\frac{1+\cos 2\alpha}{2}, \end{equation}\]

\[\begin{equation}\label{1.13}\tag{1.13} \sin^2\alpha=\frac{1-\cos 2\alpha}{2}, \end{equation}\]

\[\begin{equation}\label{1.14}\tag{1.14} \cosh^2\alpha-\sinh^2\alpha=1, \end{equation}\]

\[\begin{equation}\label{1.15}\tag{1.15} \cosh\alpha=\cosh(-\alpha)=\sqrt{\sinh^2\alpha+1}, \end{equation}\]

\[\begin{equation}\label{1.16}\tag{1.16} \sinh\alpha=-\sinh(-\alpha)=\sqrt{\cosh^2\alpha-1}, \end{equation}\]

\[\begin{equation}\label{1.17}\tag{1.17} \tanh\alpha=\frac{e^{\alpha}-e^{-\alpha}}{e^{\alpha}+e^{-\alpha}}=1-\frac{2}{e^{2\alpha}+1}=-\tanh(-\alpha), \end{equation}\]

\[\begin{equation}\label{1.18}\tag{1.18} \sin 4\alpha=4\cos^3\alpha\sin\alpha-4\cos\alpha\sin^3\alpha, \end{equation}\]

\[\begin{equation}\label{1.19}\tag{1.19} \cos 4\alpha=\cos^4\alpha+\sin^4\alpha-6\sin^2\alpha\cos^2\alpha, \end{equation}\]

\[\begin{equation}\label{1.20}\tag{1.20} \sin\alpha\sin\beta=\frac{1}{2}[\cos(\alpha-\beta)-\cos(\alpha+\beta)]. \end{equation}\]