Question 402407
If you went around a complete circle in a clock-wise
direction, which is (-) direction, once around is {{{-2pi}}}
You are back where you started at {{{0pi}}}
Now suppose you do this {{{7}}} times. You have gone 
around the circle {{{-14pi}}} times, and you are back
where you started at {{{0pi}}}. Now head in the (-)
direction (CW) {{{-pi}}} more. That puts you at {{{-pi}}}
on the circle. Now the answer is {{{sin(-pi) = 0}}}
Note that any odd number times {{{-pi}}} will put you
at {{{-pi}}}.
Hope this helps