As you can see the red graph depicts sin x while the blue depicts sin (x+(pi/3))
The effect of the pi/3 to the original function is to simply shift the graph leftwards.
The usual f(x) = sin x graph is a periodic function graph that oscillates between 1 and -1. That's the red graph.
[tex]\begin{gathered} On\text{ the red graph, at x = 0, f(x) = sin x is 0}.\text{ That's the function f(x)=sin x} \\ \text{However, on the blue graph, at x=0, f(x) = sin (0+}\frac{\pi}{3}\text{) = sin }\frac{\pi}{3}\text{ which is greater than zero} \\ \text{causing the left shift.} \end{gathered}[/tex]
