Question 958632
<pre>
7sin(2x)+7sin(x)=0

Divide every term by 7

{{{7sin(2x)/7+7sin(x)/7=0/7}}}

{{{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
                 cos(x) = {{{-1/2}}}
                   

If your problem states in the interval from 0° to 360°,
the answer is  0°,180°, 120°,240°

If your problem states in the interval from 0 to 2&#960;,
the answer is  0,&#960;,2&#960;/3,4&#960;/3 

If your problem states for all x in degrees, 
the answer is  180n°, 120°+360n°, 240180°+360n180°

If your problem states for all x (in radians), 
the answer is  n*&#960;, 2&#960;/3+2n*&#960;, 4&#960;/3+2n*&#960;

Edwin</pre>