$2\mathrm{.}2$ Express the following in the simplest form you can:

a$.sin(2ft-)+sin(2ft+)$

b$.sin2ft+sin(2ft-)$

$2\mathrm{.}3$ Sound may be modeled as sinusoidal functions. Compare the wavelength and rela$-$

tive frequency of musical notes. Use $330\frac{m}{s}$ as the speed of sound and the following

frequencies for the musical scale.

$2\mathrm{.}4$ If the solid curve in Figure $2\mathrm{.}14$ represents $sin(2t),$ what does the dotted curve rep$-$

resent? That is$,$ the dotted curve can be written in the form Asin$(2ft+)$; what are

$A,f,$ and $?$

$2\mathrm{.}5$ Decompose the signal $(1+0\mathrm{.}1cos5t)cos100t$ into a linear combination of sinusoidal

function, and find the amplitude, frequency, and phase of each component. Hint: Use

the identity for $cosacosb.$