If z = f(x + ay) + ϕ (x - ay), then
1
\(\frac{\partial^2z}{\partial x^2}=a^2\frac{\partial^2z}{\partial y^2}\)
2
\(\frac{\partial^2z}{\partial y^2}=a^2\frac{\partial^2z}{\partial x^2}\)
3
\(\frac{\partial^2z}{\partial y^2}=-\frac{1}{a^2}\frac{\partial^2z}{\partial x^2}\)
4
\(\frac{\partial^2z}{\partial x^2}=-{a^2}\frac{\partial^2z}{\partial y^2}\)
5
Not Attempted