## Precalculus (6th Edition) Blitzer

The solution is $\underline{x=1.7798,4.9214}.$
We have to compute the value: \begin{align} & \tan x=-4.7143 \\ & x={{\tan }^{-1}}\left( -4.7143 \right) \end{align} We have to calculate the equation using a calculator in radian mode: \begin{align} & \theta ={{\tan }^{-1}}\left( +4.7143 \right) \\ & \approx +4.7143 \end{align} And the value will be: ${{\tan }^{-1}}\left( +4.7143 \right)\approx 1.3618$ The tangent value is negative in II and IV quadrants. So, \begin{align} & x\approx \pi -1.3618 \\ & \approx 3.14159-1.3618 \\ & \approx 1.7798 \end{align} And another value will be: \begin{align} & x\approx 2\pi -1.3618 \\ & \approx 2\times 3.14159-1.3618 \\ & \approx 4.9214 \end{align}