Question 1025767
<pre>
      sin(2x) + sin(x) = 0
2sin(x)cos(x) + sin(x) = 0
     sin(x)[2cos(x)+1] = 0

sin(x) = 0;   2cos(x)+1 = 0
x = 0, <font face="symbol">p</font>        2cos(x) = -1
                 cos(x) = -1/2
                      x = 2<font face="symbol">p</font>/3, 4<font face="symbol">p</font>/3

Edwin</pre>