Answer:
[tex]\frac{\sqrt3}{2}[/tex]
Step-by-step explanation:
[tex]sin(A)=\frac{1}{2}[/tex]
[tex]A = \frac{\pi}{6}[/tex] //this is retrieved from looking at the unit circle
[tex]cos(A) = cos(\frac{\pi}{6}) = \frac{\sqrt3}{2}[/tex]
