let's take an example wave $Y=Cos(x)$ about $x=0$.
$dy/dx=-Sin(0)=0$
$d2y/dx2=-Cos(0)=-1$
it is important to note that one is not simply the square of the other
let's take an example wave $Y=Cos(x)$ about $x=0$.
$dy/dx=-Sin(0)=0$
$d2y/dx2=-Cos(0)=-1$
it is important to note that one is not simply the square of the other