Question 867725
sec &#963; = -4, 180° < &#963; < 270°. Find the exact value of sin &#963;/2 and cos &#963;/2
use x for &#963;
sec(x)=-4
cos(x)=-1/4
{{{cos(x/2)=sqrt((1+cos(x))/2)=sqrt((1-1/4)/2)=sqrt((3/4)/2)=sqrt(3/8)}}}
{{{sin(x/2)=sqrt((1-cos(x))/2)=sqrt((1+1/4)/2)=sqrt((5/4)/2)=sqrt(5/8)}}}