Please help! will give brainlest! locks in 30 min!

Answer:
[tex]\frac{\sqrt{2} }{2}[/tex]
Step-by-step explanation:
Simplify the expression:
sin [tex]\frac{3pi}{4}[/tex]
Rewrite the angle as a sum or difference with its reference angle:
sin (pi - [tex]\frac{pi}{4}[/tex])
Simplify the expression
(sin [tex]\frac{pi}{4}[/tex])
Evaluate the expression:
[tex]\frac{\sqrt{2} }{2}[/tex]
hope this helps and is right!! p.s. i really need brainliest :)