Upgrade subject to access all content

Find all values for $x$ for which $\sin^{2}x+2\text{sin }x+1=0$

$\cfrac{\pi}{2}+2\pi k$

$\cfrac{3\pi}{2}+2\pi k$

$\pi+2\pi k$

$\cfrac{\pi}{4}+2\pi k$

$\cfrac{2\pi}{3}+2\pi k$