Question 1103957
<br>
Presumably the equation is supposed to be
{{{S=200cos((pi/6)(t+2))+200}}}....<br>
For the sales to be 0, {{{cos((pi/6)(t+2))}}} must be -1; that means {{{(pi/6)(t+2)}}} must be equal to {{{pi}}}.<br>
{{{(pi/6)(t+2) = pi}}}
{{{(t+2)/6 = 1}}}
{{{t = 4}}}<br>
If t=0 represents January, then t=4 represents May.<br>
The equation indicates that sales are 0 in the month of May.