So the question:
is 1/r > r/(r^2+2)?
The actual answer is, "we don't have enough info." according to the book, but can't we cross multiply, giving us:
r^2+2 > r^2
Which would be true in all cases, isn't it?
We supposedly would have enough info if we knew also knew that r>0, but what difference will that make? Squaring anything would make r^2 a positive number anyway, right?
Can anyone tell me what I'm missing here?