Answer and Step-by-step explanation:
To find the angles between the lines, we can use the formula:
tanα = |ms - mr| / | 1 + ms.mr|
where ms and mr are the linear coefficients of the lines you want to find. It always finds the smaller angle formed.
Let's find all the angles from the triangles formed.
y=x ms = 1
y=2x mr = 2
tanα = |1 - 2| / | 1 + 1.2|
tanα = |-1| / | 1 + 2|
tanα = |-1/3|
tanα = 1/3
α = tan⁻¹1/3
α = 18.4°
y=x ms = 1
y=-4 mr = 0
tanα = |1 - 0| / | 1 + 1.0|
tanα = |1| / | 1 + 0|
tanα = |1/1|
tanα = 1
α = tan⁻¹1
α = 45°
y=2x ms = 2
y=-4 mr = 0
tanα = |2 - 0| / | 1 + 2.0|
tanα = |2| / | 1 + 0|
tanα = |2/1|
tanα = 2
α = tan⁻¹2
α = 63.4°
As these 2 lines are in both triangles, the suplement of this angle is also asked, so, 180° - 63.4° = 116.6°
For y=2x and y=-4, it's the same: α = 63.4°
y=2x ms = 2
y=-2x mr = -2
tanα = |2 - (-2)| / | 1 + 2.(-2)|
tanα = |4| / | 1 - 4|
tanα = |4/3|
tanα = 4/3
α = tan⁻¹ 4/3
α = 53.1°