If θ is the angle between the lines joining the points (0, 0) and B(2, 3), and the points C(2, -2) and D(3, 5), show that .

The given points are A(0,0),B(2,3) and C(2,-2),D(3,5).

The slope of line AB is

And the slope of line CD is

We know that angle between two lines with their slopes as m₁ and m₂ is given by

Hence proved.