Question 616402
Without a second variable the equation says that y = a number which is the equation of a horizontal line:
{{{y = (1/3)sin(pi/2-pi)}}}
{{{y = (1/3)sin(-pi/2)}}}
{{{y = (1/3)(-1)}}}
{{{y = -1/3}}}
This is not a periodic function so it has no period.