Answer:
(√2 + √6)/4.
Step-by-step explanation:
Use the addition formula
sin (A+ B) = sinAcosB + cosAsinB
sin (7pi/12) = sin( 3pi/12 + 4pi/12)
= sin(pi/4 + pi/3) = sin pi/4 cos pi/3 + cos pi/4 sin pi/3
= 1/√2 * 1/2 + 1/√2 * √3/2 (using the 45-45-90 and 30-60-90 triangles)
= 1 / 2√2 + √3/2√2
= √2/4 + √6/4
= (√2 + √6)/4
