#### Answer

$y=\sin (x+\frac{\pi}{3})$

#### Work Step by Step

The graph is that of $y=\sin x$ except that it has been translated $\frac{\pi}{3}$ units to the left.
Sine graphs that are translated right or left are of the form $y=\sin (x-d)$. According to the rules of translating graphs, if the translation is $d$ units to the right, $d$ is greater than zero. Conversely, if the translation is $|d|$ units to the left, $d$ is less than zero.
Therefore, as the graph has been translated $\frac{\pi}{3}$ units to the left, $d=-\frac{\pi}{3}$. Therefore, its equation is
$y=\sin [x-(-\frac{\pi}{3})]=\sin [x+\frac{\pi}{3}]=\sin (x+\frac{\pi}{3})$.