The inclination of the line which is angular bisector of coordinate axes in the second quadrant is (in radians)

The slope of line which makes equal angles with axes and lies in the second quadrant is  $m=-1$
Therefore, inclination of the above line is   $\theta ={\tan }^{-1}\left(-1\right)=\frac{3\pi }{4}=2.36\text{\hspace{0.17em}radians}$