You can see two intersecting lines (a and b) in red. Equation of the lines is written in slope intercept form(y=mx+c). Line ‘a’ makesan angle α with the positive direction of x axis(shown in blue color)and line ‘b’ makes an angle β with the positive direction of x axis(shown in blue color). A is a free point on line a and B is a free point in line b. You can move these points. Angle between these two lines (У) is also shown in black color

Questions to think about
Compare the values of α, β and У what do we get?
Calculate the value of tan У and compare it with (〖(m〗_1-m_2))/(1+m_1 m_2 ), what do we get?