Question 39058
Find the exact value by using half-angle formula.
a)sin22.5=sin(45/2)= sqrt[(1-cos(45))/2]
 = sqrt[(1-(sqrt(2)/2))/2]=[sqrt[(2-sqrt(2)]]/2
=0.38268343...   

b)sin(7pie/8)= sin[(1/2)(7pi/4)]=
sqrt[(1-cos(7pi/4))/2]=sqrt[1-(sqrt(2)/2)/2]
=[sqrt[2-sqrt(2)]]/2=0.38268343...

Cheers,
Stan H.