Matrices and Determinants - Hard

a > 0

b > 0

c > 0

are respectively the

p

th,

q

th,

r

th terms of a GP, then the value of the determinant

\begin{vmatrix} \log a & p & 1 \\ \log b & q & 1 \\ \log c & r & 1 \end{vmatrix}