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Trigonometry · Unit-Circle

Evaluate cos(2*pi/3)

\cos{\left(\frac{2 \cdot \pi}{3} \right)}

Step by step

  1. \cos{\left(2 \pi \frac{1}{3} \right)} = - \frac{1}{2}

    Exact value from the unit circle: cos(2·π·(1/3)) = -1/2.

Reveal the answer
- \frac{1}{2}