Let Γ₁ and Γ₂ be arbitrary circles that intersect at points P and Q.

Prove or disprove that there exist points M and N such that

(1) M ∈ Γ₁\{P,Q},
(2) N ∈ Γ₂\{P,Q},
(3) M, N, and P are collinear, and
(4) ∠MQP = ∠NQP.

If they exist, prove or disprove that they can be constructed with
straightedge and compass.

Here is a link to Wolfram MathWorld:
Definition of Set Difference

(In reply to Solution by Harry)

1) In your proof you have /MPR = /NPS (which it is), but don't you have to show that S lies on PR?

Posted by Bractals on 2013-11-14 01:26:09