Question

Find the angle between X-axis and the line joining the points (3, −1) and (4, −2).

Answer 1

Let the given points be A (3, −1) and B (4, −2).

$\therefore$ Slope of AB = $\frac{-2+1}{4-3}=-1$

Let $\theta$ be the angle between the x-axis and AB.

$$\begin{gathered} \therefore \tan \theta =-1 \\ \Rightarrow \theta ={\tan }^{-1}\left(-1\right)=\frac{3\mathrm{\pi }}{4} \end{gathered}$$

Hence, the angle between the x-axis and the line joining the points (3, −1) and (4, −2) is $\frac{3\mathrm{\pi }}{4}$.