How to convert this into a bessel equation

Question

I am trying to convert this into a Bessel equation of the form

$$x^2y'' +xy' +(x^2 -n^2)y = 0$$ the equation is :

$$ rR''(r) + R'(r) + \lambda^2r(R(r)) = 0 $$

Can you please indicate what type of substitution should i make.

Thank You very much

Anupam

Answer 1

If you set $r=\lambda x$ you get a Bessel differential equation with $n=0$.