Question

find the angle between the x-axis and the line joining the points (3,-1)and (4,-2)

Answer 1

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

and we will consider m be the slope of the line AB.

m = -2-(-1)/4-3

= -2 + 1/1

= -1

[∴ m = (y₂ - y₁) / (x₂ - x₁)]

Now we will consider θ = m = -1

= - tan 45°

= tan (180° - 45°)

= tan 135°

θ = 135°

So the required angle is 135°

Answer 2

Step-by-step explanation:

slope of the line joining the points (3,−1) and (4,−2) is m=

4−3

−2−(−1)

=−2+1=−1

Now the inclination (θ) of the line joining the points (3,1) and (4,2) is given by tanθ=−1

⇒θ=(90

∘

+45

∘

)=135

∘

A slope of the line is an inclination with the x-axis.

Thus, the angle between x-axis and the line joining the points (3,1) and (4,2) is 135

∘