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Question
Find the angle between the X-axis and the line joining the points (3, −1) and (4, −2).
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Solution
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.
\[\therefore \tan\theta = - 1\]
\[ \Rightarrow \theta = \tan^{- 1} \left( - 1 \right) = {135}^\circ\]
Hence, the angle between the x-axis and the line joining the points (3, −1) and (4, −2) is \[{135}^\circ\].
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