ok in this problem im supposed to use the substitution x = e^t to transform the given Cauchy-Euler equation to a differential equation with constant coefficients.
x^2y'' +9xy' -20y=0
im not sure how to start this problem
maybe dy/dx= (dy/dt)(dt/dx) = (dy/dt)e^t
so then could i say d2y/dx^2 = (e^t)d2y/dt^2<---- ?
maybe then i could substitute back into the equation? i dunnno..
any help would be appreciated thanks in advance.