Answer:
C
Step-by-step explanation:
Using the trig. identity
sin²x + cos²x = 1 ⇒ cosx = ± [tex]\sqrt{1-sin^2x}[/tex]
Here sinθ = [tex]\frac{1}{2}[/tex] , thus
cosθ = ± [tex]\sqrt{1-(\frac{1}{2})^2 }[/tex] = ± [tex]\sqrt{1-\frac{1}{4} }[/tex] = ± [tex]\sqrt{\frac{3}{4} }[/tex] = ± [tex]\frac{\sqrt{3} }{2}[/tex]
Since 0 ≤ θ > 90 then cosθ > 0 , thus
cosθ = [tex]\frac{\sqrt{3} }{2}[/tex] → C
