Answer:
The positive value is 1/2
Step-by-step explanation:
we know that
The sine of a half-angle identity is given by the formula
[tex]sin^2(\frac{A}{2})=\frac{1-cos(A)}{2}[/tex]
we have
[tex]cos(A)=\frac{1}{2}[/tex]
substitute
[tex]sin^2(\frac{A}{2})=\frac{1-\frac{1}{2}}{2}[/tex]
[tex]sin^2(\frac{A}{2})=\frac{\frac{1}{2}}{2}[/tex]
[tex]sin^2(\frac{A}{2})=\frac{1}{4}[/tex]
square root both sides
[tex]sin(\frac{A}{2})=\pm\frac{1}{2}[/tex]
therefore
The positive value is 1/2
