Evaluate the trigonometric function.Round your answer to four decimal places. $$\tan \left( - \frac { \pi } { 8 } \right)$$
A)0.5858
B)-0.4142
C)0.0858
D)2.5858
E)1.5858

Question

Evaluate the trigonometric function.Round your answer to four decimal places.​ $$\tan \left( - \frac { \pi } { 8 } \right)$$ ​
A)0.5858
B)-0.4142
C)0.0858
D)2.5858
E)1.5858

Quizplus · Accepted Answer

The tangent of a negative angle is the negative of the tangent of the angle. $\tan(-x) = -\tan(x)$. For $\tan\left(-\frac{\pi}{8}\right)$, we can use the half-angle identity for tangent, or recognize it as the negative of $\tan\left(\frac{\pi}{8}\right)$. The exact value of $\tan\left(\frac{\pi}{8}\right)$ is not commonly memorized, but calculating or looking it up, we find it is approximately -0.4142, hence the correct answer is B.

Evaluate the Trigonometric Function tan⁡(−π8)\tan \left( - \frac { \pi } { 8 } \right)tan(−8π​)

Evaluate the Trigonometric Function $\tan \left( - \frac { \pi } { 8 } \right)$