c OwwwwebassignnetwebStudentAssignmentResponseslastdep163045

c Owww.webassign.net/web/Student/Assignment-Responses/last?dep-16304524 Use an appropriate Half-Angle Formula to find the exact value of the expression. Need Help? Rdaich | 7.1 points SAgTrig4 7.3038 MI. Find sn(co ) and tan() from the given information. cos(x)-4, 1800

Solution

cos ( 9pi/8 )

half angle formula for cos ( theta / 2 ) = +- sqrt {( 1+ cos theta )/2 }

9pi/8 = 1/2 * 9pi/4

cos 9pi/4 = sqrt 2 / 2

cos 9pi/8 = + - sqrt { 1 + sqrt 2/2 ) / 2 }

= +- sqrt {( 2 + sqrt 2 / 4 )}

cos 9pi/8 = +- sqrt ( 2 + sqrt 2 ) / 2