sinπ/16平方-cosπ/16平方
＝－cosπ/8
=-√[(1+cosπ/4)/2]
=-1/2*√(2+√2)
tan(5π/24)除以1-[tan（5π/24）的平方]
=1/2*tan(5π/12)
=1/2*[1-cos(5/6)]/sin(5π/6)
=1/2*[1+√3/2]/(1/2)
=1+√3/2