Find the distance between the points (a cos thita , a sin thita ) and ( - a cos thita , a sin thita)

Find the distance between the points (a cos thita , a sin thita ) and

1.	Find the distance between the points (a cos thita , a sin thita ) and ( - a cos thita , a sin thita)
Answer» How u do this sushma ca u explain 2cos thita Please answer me