If pqr =1, then prove that :

1/ ( 1+p+q ^-1 ) + 1 / (1+q+r^-1 ) + 1 / (1+r + p ^{- 1} ) = 1

(1/1+p+1/q) +(1/1+q+1/r) + (1/1+r+1/p) = 1

the solution of this question is given in the hardcopy of the maths