Answer:
33
Step-by-step explanation:
The answer is 0
Let me tell you why
first plug in the numbers
.5(18+14)-(18-14)^2
(9+7)-(4)^2
16-16
0
Sin angle that equals the 1/2 value is the 30 degree on the 1st Quadrant.
The angle of 30 degree on the 3rd Quadrant is equivalent to (formula and circle in the 1st photo) 180 + 30 = 210°.
So theta = 210° (3rd Quadrant) = 30° (1st Quadrant).

Now just transfer the cos 30° to the 3rd Quadrant and the signal will be negative (as shown in the 2nd photo attached).
If you put it in fraction form and use PEMDAS to find the answer