Differential Equations

$\left[y-x \frac{d y}{d x}\right]^2=1-\left[\frac{d y}{d x}\right]^2$

$\left[y-x \frac{d y}{d x}\right]^2=1+\left[\frac{d y}{d x}\right]^2$

$\left[y+x \frac{d y}{d x}\right]^2=1+\left[\frac{d y}{d x}\right]^2$

$\left[y+x \frac{d y}{d x}\right]^2=1-\left[\frac{d y}{d x}\right]^2$