Differential Equations

A Cauchy-Euler equidimensional ODE $x^2 \frac{d^2y}{dx^2} + p x \frac{dy}{dx} + q y = 0$ is transformed into an ODE with constant coefficients by the substitution:

Options:

• (A) $x = e^z$ (or $z = \ln x$)
• (B) $x = \sin z$
• (C) $x = z^2$
• (D) $x = 1/z$