>>869
{x^m(ax+b)^n}'
= (x^m)'*(ax+b)^n + x^m*{(ax+b)^n}'
= mx^(m-1)*(ax+b)^n + x^m*n(ax+b)^(n-1)*(ax+b)'
= mx^(m-1)(ax+b)^n + anx^m(ax+b)^(n-1)