Consider the following statements:
Assertion (A): When \( x, y, z \) are positive numbers, then
\[ \tan^{-1}\left( \sqrt{\frac{x(x+y+z)}{yz}} \right) + \tan^{-1}\left( \sqrt{\frac{y(x+y+z)}{xz}} \right) + \tan^{-1}\left( \sqrt{\frac{z(x+y+z)}{xy}} \right) = \pi \]
Reason (R): \( \tan^{-1}a + \tan^{-1}b = \tan^{-1}\left( \frac{a+b}{1-ab} \right) \) if \( a>0 \) and \( b>0 \).