Trigonometry, just the first one, will mark as brainliest if helpful

Answer:
a = -0.5
b = −1.73
c = −0.70
d = [tex]-\frac{\sqrt{2} }{2}[/tex] ≈ -0.70710678
Step-by-step explanation:
EXPLAIN Q(a):
sin(−30)
Use the property sin(−x)=−sin(x).
−sin(30)
Get the value of sin(30) from trigonometric values table.
-0.5