นิพจน์ 6: "a" equals left brace, alpha less than 60 : StartFraction, "r" Over sin left parenthesis, StartNestedFraction, alpha NestedOver 2 , EndNestedFraction , right parenthesis , EndFraction , alpha greater than or equal to 60 : 2 "r" , right bracea=α<60:rsinα2,α≥60:2r