Introductio in analysin infinitorum

AC DIVISIONE ANGULORUM. 205 CAP. XIV. $fin. z = 1 fin. z$ $fin. 2z = 2 fin. z. fin. (\frac{\pi}{2} - z)$ $fin. 3z = 4 fin. z. fin. (\frac{\pi}{3} - z). fin. (\frac{\pi}{3} + z)$ $fin. 4z = 8 fin. z. fin. (\frac{\pi}{4} - z). fin. (\frac{\pi}{4} + z). fin. (\frac{2\pi}{4} - z)$ $fin. 5z = 16 fin. z. fin. (\frac{\pi}{5} - z). fin. (\frac{\pi}{5} + z). fin. (\frac{2\pi}{5} - z) \times fin. (\frac{2\pi}{5} + z)$ $fin. 6z = 32 fin. z. fin. (\frac{\pi}{6} - z). fin. (\frac{\pi}{6} + z). fin. (\frac{2\pi}{6} - z) \times fin. (\frac{2\pi}{6} + z). fin. (\frac{3\pi}{6} - z)$ &c. 242. Cum deinde fit $\frac{fin. 2nz}{fin. nz} = 2cof.nz$, Cosinus Angulorum multiplorum simili modo per Factores exprimentur. $cof. z = 1 fin. (\frac{\pi}{2} - z)$ $cof. 2z = 2 fin. (\frac{\pi}{4} - z). fin. (\frac{\pi}{4} + z)$ $cof. 3z = 4 fin. (\frac{\pi}{6} - z). fin. (\frac{\pi}{6} + z). fin. (\frac{3\pi}{6} - z)$ $cof. 4z = 8 fin. (\frac{\pi}{8} - z). fin. (\frac{\pi}{8} + z). fin. (\frac{3\pi}{8} - z) \times fin. (\frac{3\pi}{8} + z)$ $cof. 5z = 16 fin. (\frac{\pi}{10} - z). fin. (\frac{\pi}{10} + z). fin. (\frac{3\pi}{10} - z) \times fin. (\frac{3\pi}{10} + z). fin. (\frac{5\pi}{10} - z)$ & generaliter Cc 3 cof.