Verify That the Equation Is an Identity $P _ { 1 } = 0.003 \sin ( 14 \pi t )$

Verify that the equation is an identity.
-Two low-frequency sound waves with similar frequencies, producing the pressures $P _ { 1 } = 0.003 \sin ( 14 \pi t )$ and $P _ { 2 } = 0.002 \sin ( 24 \pi t )$ , combine to form a pressure $P = P _ { 1 } + P _ { 2 }$ . The variable $\mathrm { t }$ is time measured in seconds. Graph $\mathrm { P }$ in $[ 0,1.2 , .05 ]$ by $[ - 0.01,0.01,0.001 ]$ and use the graph to determine the frequency of the displayed beats.

A) 7 beats per second
B) 10 beats per second
C) 5 beats per second
D) 12 beats per second