Key points to solve the problem:
• The idea of distance formula- Distance between two points P(x1, y1) and Q(x2, y2) is given by- PQ = \(\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\)
Given,
Two points P and Q subtends an angle α at the origin as shown in figure:
From the figure we can see that points O,P and Q forms a triangle.
Clearly in ΔOPQ we have:
From equation 1 and 2 we have: