I know that y>=x-1
and if I do it for 0 to 1 I don't get in the end that the probabilty =1
Your response to gabbagabbahey's question was confusing. In your previous post, you answered, it was because you knew [itex]y \ge x-1[/itex]. The "x-1" suggested to me you somehow got that condition from the constraint [itex]x+y \le 1[/itex], and my point was that the constraint can only lead to [itex]y \le 1-x[/itex], the upper limit of the integral. There's no way you can get [itex]y \ge x-1[/itex] from it.right... so that's why I chose the integral limits for dy to be from x to 1-x.
Is it wrong?