Question 923529
Determine all solutions of the equation in radians
find cosx/2, given that sec x = 4 and x terminates in 0<x<pi/2.
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cosx=1/secx=1/4 (In quadrant I where cos>0)
{{{cos(x/2)=sqrt((1+cosx)/2)=sqrt((1+1/4)/2)=sqrt(5/4)/2=sqrt(5/8))}}}
cos(x/2)=&#8730;(5/8)
use inverse cos key on calculator set to radians,then punch in &#8730;(5/8)
cos(x/2)&#8776;0.659 radians