Question 817265
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Hi,
2*sin^2(x)+3*sin(x)+1=0
(2sin(x)+1)(sin(x) + 1) = 0
(2sin(x)+1) = 0 , sin(x) = -1/2
(sin(x) + 1) = 0, sin(x) = -1 
See(cos(x), sin(x)) reference below:
<img src='http://img9.imageshack.us/img9/2032/mfpe.png' border='0'/></a>