Question 772880
Find the 4 solutions in the interval [0, 2pi), for the equation, 
2cos x sin x + sin x = zero
(sin x)(2cos x+1)=0
..
sinx=0
x=0, π
..
2cos x+1=0
cos x=-1/2
x=2π/3, 4π/3
..
4 solutions: 0, π, 2π/3, 4π/3