Determine the acute angle between the line passing through the points A(-2;1/5) and B(0;1) and the line passing through the points C(1;0) and D(-2;6)
The lines have slopes 2/5 and 2
α = arctan(2/5)
β = arctan(2)
the angle between them is β-α
α = arctan(2/5)
β = arctan(2)
the angle between them is β-α