I don't understand this step solving partial derivative equation

Question

(1) $v_{xx}+3v_{yy}-44v=0$

Let $x'=x, y'= \sqrt{3}y $

Substitute this value in (1) equation

$v_{x'x'}+v_{y'y'}-44v=0$

I've just started learning PDE. It is so confusing that coefficient of $v_{y'y'}$ becomes 1. Could someone help me?

Answer 1

Hint:

use twice the chain rule: $$ \frac{\partial v}{\partial y'}=\frac{\partial v}{\partial y}\frac{\partial y}{\partial y'} $$