799. What does $\sin 5 x$ mean, where 5 is an abstract number (not $5^{\circ}$ or $5^{\prime}$)? How can the value of this function be calculated using ordinary tables of angular functions?
799. The absólute unit of angle is the radian, i.e., the angle that cuts from a circle an arc equal in length to its radius, or an angle of $57^{\circ} 17^{\prime} 44^{\prime \prime} 8^{\prime \prime \prime}$ or $209284^{\prime \prime}$. Therefore, an angle of 5, expressed in degrees, minutes, and seconds, equals $286^{\circ} 28^{\prime} 44^{\prime \prime}$; therefore

$$
\begin{gathered}
\sin 5=\sin 286^{\circ} 28^{\prime} 44^{\prime \prime}=\sin \left(270^{\circ}+16^{\circ} 28^{\prime} 44^{\prime \prime}\right)= \\
=-\cos 16^{\circ} 28^{\prime} 44^{\prime \prime}=-0.959
\end{gathered}
$$