Is asking practice exam questions on the web cheating? Is asking practice exam questions released by a professor on the web cheating?
If you asked questions from a past exam, that was already released, and graded, is that cheating?
No, if you aren't going to be graded on them it isn't cheating. 

But it is foolish. 

The point of the questions is to give you practice in solving them, not to obtain answers that the professor already has. 

If you don't practice your craft you will never get very good at it. 

Moreover, just seeing an answer will very likely give you almost no insight in what it takes to actually solve such problems when face with them in a more important context. You may actually be doing yourself harm by reading answers. 

Much better is to work on the problems yourself, and, when you get stuck, ask the professor for help. They will, I hope, give you just enough of a boost to get you going again, rather than so much that it denies you the insight. Strangers on the web are not the best source of your education.