



 
Hi Yamama, Write the equation as \[2cos^2 x + sin x 2 = 0\] and use the fact that \[\sin^2(x) + \cos^2(x) = 1\] to express your equation as a quadratic in $\sin(x).$ Solve the quadratic. If you have an app on your computer that will graph equations you can use it to plot the graph of \[y = 2cos^2 x + sin x 2 \] to verify that you have found all the solutions. Penny  


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