Answer:
C
Step-by-step explanation:
using the addition formula for sine
sin(A + B) = sinAcosB + cosAsinB
note that [tex]\frac{7\pi }{12}[/tex] = [tex]\frac{\pi }{3}[/tex] + [tex]\frac{\pi }{4}[/tex] , then
sin [tex]\frac{7\pi }{12}[/tex]
= sin([tex]\frac{\pi }{3}[/tex] + [tex]\frac{\pi }{4}[/tex] )
= sin[tex]\frac{\pi }{3}[/tex]cos[tex]\frac{\pi }{4}[/tex] + cos[tex]\frac{\pi }{3}[/tex]sin[tex]\frac{\pi }{4}[/tex]
= ( [tex]\frac{\sqrt{3} }{2}[/tex] × [tex]\frac{\sqrt{2} }{2}[/tex] ) + ([tex]\frac{1}{2}[/tex] × [tex]\frac{\sqrt{2} }{2}[/tex] )
= [tex]\frac{\sqrt{6} }{4}[/tex] + [tex]\frac{\sqrt{2} }{4}[/tex]
= [tex]\frac{\sqrt{2}+\sqrt{6} }{4}[/tex]
