Rook + Knight versus Queen

MARattigan
pfren wrote:

In the first diagram (#15), Black looks safe after 1...Ra2.

In the second one, 1...Ra2 drops the rook to Qd5+, so Black has to put the rook to the vulnreable b2 square, and white has several tactical tricks after that. White may well be winning but I am not sure about the way.

Correct. 

White draws by Ra2 in the first diagram.

White is winning in both after 1...Rb2, but the analysis is involved. (Nalimov takes nine moves to convert into queen v. rook after 2.Qg3 - the only move to win in both).

That was really the point of the post. Previous posts had pointed out that the defense in OP's position is trivial and the uninformed reader may have concluded that the endgame as a whole is trivial. If they study the diagrams they may conclude that it's not so trivial after all.