Since , we need to find the n-1th derivative of the integrand. Write then we differentiate each expression n-1 times to give us Changing to polars and applying De Moivre's gives us:
Since , we need to find the n-1th derivative of the integrand. Write then we differentiate each expression n-1 times to give us Changing to polars and applying De Moivre's gives us:
that's a nice approach but you made a mistake in your solution somewhere because your answer is correct only for another way is to let then an easy
induction shows that: writing everything in terms of will give us: