Problem 4.10

Using graphical means, find an amplitude $a$ of oscillations resulting from the superposition of the following oscillations of the same direction: (a) $x_{1}=3.0 \cos (\omega t+\pi / 3), \quad x_{2}=8.0 \sin (\omega t+\pi / 6)$ (b) $x_{1}=3.0 \cos \omega t, x_{2}=5.0 \cos (\omega t+\pi / 4), x_{3}=6.0 \sin \omega t$