A common sinusoidal function is:
[tex]y = asin(bx)[/tex]
so,always amplitude is a, so a=6
and we know period is:
[tex]p = \frac{ |b| }{2\pi} [/tex]
so
[tex] \frac{ |b| }{2\pi} = \frac{2\pi}{3} [/tex]
[tex]b = + or - \frac{4 {\pi}^{2} }{3} [/tex]
and we have 2 equations that while we can consider which is appropriate ,to have its graph!
[tex]6 \sin( \frac{4 {\pi}^{2} }{3}x ) [/tex]
and when you want to shift it 1 unit left we have:
[tex]6 \sin( \frac{4 {\pi}^{2} }{3}x +1) [/tex]
