Answer:
Step-by-step explanation:
Given that angle A is in IV quadrant
So A/2 would be in II quadrant.
sin A = -1/3
cos A = [tex]\sqrt{1-sin^2 A} =\frac{2\sqrt{2} }{3}[/tex]
(cos A is positive since in IV quadrant)
Using this we can find cos A/2
[tex]cosA = 2cos^2 \frac{A}{2} -1\\Or cos \frac{A}{2} =-\sqrt{\frac{1+cosA}{2} } =-\sqrt{\frac{3+2\sqrt{2} }{6} }[/tex]
