For a function f(x) , let . d^x(f(x)) d x^i |_ x=a denotes its i -th derivative with respect to x evaluated at x=a . Consider the matrix A= (a_ i, j )_ n m of n( 1) rows and m( 1) columns, with a_ i, j = ( . d^i x^n d x^i |_ x-1 ) / ( . d^j y^m d y^j |_ y-1 ) Let p_i= a_ i, j : j=1,2, , m , q_j= a_ i, j : i=1,2, , n , p= p_i: i=1,2, , n and q= q_j: j=1,2, , m . Then