Question

find the distance between (p,q) and (q,p)​

Answer 1

$d = \sqrt{(p - q {)}^{2} + (q - p {)}^{2} }$

$d = \sqrt{( {p}^{2} + {q}^{2} - 2pq) + ( {q}^{2} + {p}^{2} - 2pq) }$

$d = \sqrt{ {p}^{2} + {q}^{2} - 2pq + {q}^{2} + {p}^{2} - 2pq}$

$d = \sqrt{( {p}^{2} + {p}^{2}) + ( {q}^{2} + {q}^{2} ) + ( - 2pq - 2pq) }$

$d = \sqrt{2 {p}^{2} + 2 {q}^{2} - 4pq}$