Find the exact value of the given expression.

Question

Find the exact value of the given expression. 

sin(2π/3 - 5π/4)

Answer 1

sin(2π/3 - 5π/4) = sin(- 7π/12)= - sin(5π/12) = - sin(π/6 + π/4) = - (sinπ/6cosπ/4 + cosπ/6sinπ/4) = - (√2/4 + √6/4) = - (√2 + √6)/4