Question: If pqr = 1 then,`(1/(1 + p + q^-1) + 1/(1 + q + r^ -1) + 1/(1 + r + p^-1)) = ?`
A
B
C
D
`0`
B
`1/pq`
C
`pq`
D
`1`
Note: Given Exp.`q/(q + pq + 1) + r/(r + qr + 1) + p/(p + pr 1)`
`= q/(q + pq + 1) + 1/(1 + q + pq) + pq/(pq + 1 q) [:. r = 1/pq]`
`= (q + 1 + pq)/(q + 1 + pq)`
`= 1`