Math Forum :: View topic – differentiation

it is known that for y=xu, where u is a function of x, then y(n)=xu(n)+nu(n-1), the brackets means differentiate to n or n-1 times. then there’s a function y=x^(n-1)e^(1/x), ( ther brackets means powers here)

i dont know how to use the result above to find y(n). i suppose at this stage the question only allows us to use methods not other than simple differentation and leibniz rule. but can we just simply use the first result to deduce the answer?[/img]