Show that, for all non-zero values of the constant \(k\), the curve
$$y = \frac { k x ^ { 2 } - 1 } { k x ^ { 2 } + 1 }$$
has exactly one stationary point.
Show that, for all non-zero values of the constant \(m\), the curve
$$y = \mathrm { e } ^ { m x } \left( x ^ { 2 } + m x \right)$$
has exactly two stationary points.