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National
Easy
Trigonometry
10–12
What is the exact value of
cos
2
π
3
\cos\frac{2\pi}{3}
cos
3
2
π
?
Qual é o valor exato de
cos
2
π
3
\cos\frac{2\pi}{3}
cos
3
2
π
?
Answer options
A.
−
3
2
-\frac{\sqrt{3}}{2}
−
2
3
B.
3
2
\frac{\sqrt{3}}{2}
2
3
C.
−
1
2
-\frac{1}{2}
−
2
1
D.
1
2
\frac{1}{2}
2
1
Check Answer
Solution
Step 1 of 3
1.
2
π
3
\frac{2\pi}{3}
3
2
π
lies in the second quadrant, where the cosine is negative.
Next step
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