Question 312079
Typically repeating functions are drawn over at least one period.
{{{ graph( 300, 300, -7, 7, -3, 3, -2*cos(2*x+pi/2)) }}} 
One period of this function would be {{{pi}}}.
What is your question?
{{{ graph( 300, 300, -2, 2, -3, 3, -2*cos(2*x+pi/2)) }}}