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Compute $ an left( frac{4pi}{3}
ight)$ using the unit circle

Answer 1

Abigail Nelson

Chloe Evans

To find $\tan \left( \frac{4\pi}{3} \right)$, we use the unit circle.

The angle $\frac{4\pi}{3}$ is in the third quadrant where tangent is positive since both sine and cosine are negative and $\tan\theta = \frac{\sin\theta}{\cos\theta}$

The reference angle for $\frac{4\pi}{3}$ is $\frac{4\pi}{3} – \pi = \frac{\pi}{3}. $

Therefore, $\sin\left(\frac{4\pi}{3}\right) = -\sin\left( \frac{\pi}{3} \right) = -\frac{\sqrt{3}}{2}$ and $\cos\left(\frac{4\pi}{3}\right) = -\cos\left( \frac{\pi}{3} \right) = -\frac{1}{2}.$

Hence,

$ \tan \left( \frac{4\pi}{3} \right) = \frac{\sin \left( \frac{4\pi}{3} \right)}{\cos \left( \frac{4\pi}{3} \right)} = \frac{-\frac{\sqrt{3}}{2}}{-\frac{1}{2}} = \sqrt{3} $

Answer 2

Alex Thompson

Michael Moore

First, locate $frac{4pi}{3}$ on the unit circle. This angle lies in the third quadrant.

The coordinates of the point corresponding to $frac{4pi}{3}$ are $(-frac{1}{2}, -frac{sqrt{3}}{2})$.

The tangent function is defined as the ratio of the y-coordinate to the x-coordinate.

Therefore,

$ an left( frac{4pi}{3}
ight) = frac{y}{x} = frac{-frac{sqrt{3}}{2}}{-frac{1}{2}} = sqrt{3} $

Answer 3

Amelia Mitchell

Christopher Garcia

Angle $frac{4pi}{3}$ is in the third quadrant.

The coordinates are $(-frac{1}{2}, -frac{sqrt{3}}{2})$.

So,

$ an left( frac{4pi}{3}
ight) = sqrt{3} $