Let and be the points on the circle that correspond to central angles and respectively

MATHEMATICS · Subjective · A Level · Mathematics · Trigonometry · Trigonometry

Problem

Let

P

and

Q

be the points on the circle

x^2+y^2=25

that correspond to central angles

x^\circ

and

y^\circ

respectively, where

0<x<y<180

. Prove that the length

PQ

10\sin\dfrac{(y-x)}{2}