trig
posted by Sandy .
find the exact value by using the appropriate halfangle identity:
sin(5pi/12)

Some students can "think" better in degrees than radians, so 5π/12 rd = 75°
sin75 = sin(30+45)
= sin30cos45 + cos30sin45
= (1/2)√2/2 + (√3/2)(√2/2)
= (√2 + √6)/4