Answer:
Your question is incomplete, please edit it.
It could be anything through 456,783 to 459,999.
hope this helps :)
15) factor out cos: cos(x)(sin(x)+1)=0
Now this is true when either cos(x)=0 (x=pi/2 and 3pi/2)
Or when sin(x)=-1 (x=3pi/2)
So it's solutions are pi/2 and 3pi/2
