Assertion (A): For any two integers \(a\) and \(b\), the value of \((a + b)^{2}\) always greater than \(a^2 + b^2\) only when \(ab>0\).
 
Reason (R): The relation between \(a^2 + b^2\) and \((a+b)^2\) differs depending on the value of \(ab\).