qqp question1: If [math]x + y = 2[/math] and [math] x^2 + y^2 = 2[/math], what is the value of [math]xy[/math]? question2: What would be an intuitive way of seeing that this math expression: |x|^2 + (y - |x|^(2/3)) ^2 = 1 plots as a heart?