Bunuel
If |x| ≠ |y| ≠ 0, is \(\frac{x^2}{x^2 - y^2} > \frac{y^2 - x^2}{y^2}\) ?
(1) \(|x - y| > 1\)
(2) \(|x| < |y| \)
Let's try to solve the premise first
\(\frac{x^2}{x^2 - y^2} > \frac{y^2 - x^2}{y^2}\)
\(\frac{x^2}{x^2 - y^2} - \frac{y^2 - x^2}{y^2} > 0\)
\(\frac{x^2}{x^2 - y^2} + \frac{x^2 - y^2}{y^2} > 0\)
\(\frac{ x^2y^2 + (x^2 -y^2)^2}{ (x^2 - y^2)y^2} > 0\)
Note all the terms except \((x^2 - y^2)\) is positive in this case.
Hence, for the expression to hold true \(x^2 - y^2 > 0\)
Taking square root on both sides
|x| > |y|
Hence, we need to find if |x| > |y|
Statement 1(1) |x−y|>1
Case 1-------- x --------- y -------- 0 -------
Ex: x = -100 | y = -1
|x| > |y| -- Yes !
Case 2--------- y -------- 0 - x -----
Ex: x = 1 | y = -100
|x| > |y| -- No !
This statement is not sufficient.
We can eliminate A and D.
Statement 2(2) \(|x| < |y| \)
This statement provides us with a definite answer. Hence sufficient.
Option B