Question

4синус ²x + 4cинус x + 1 = 0

Answer 1

$4Sin^{2}x+4Sinx+1=0\\\\(2Sinx+1)^{2} =0\\\\2Sinx+1=0\\\\Sinx=-\frac{1}{2}\\\\x=(-1)^{n}arcSin(-\frac{1}{2})+\pi n,n\in Z\\\\x=(-1)^{n+1}arcSin\frac{1}{2}+\pi n,n\in Z\\\\x=(-1)^{n+1}\frac{\pi }{6}+\pi n,n\in Z$