Techniques of Differentiation - Derivatives of Trigonometric Functions

The equation of a curve is \(y = \frac{\sin x - 2}{\cos x}.\)

1. Obtain an expression for \(\frac{\mathrm{d}y}{\mathrm{d}x}\).
2. The point \(P\) moves along the curve such that its \(x\)-coordinate is decreasing at a constant rate of \(0.2\) unit/s. Find the rate of change of the \(y\)-coordinate \(P\) when \(x = \frac{\pi}{4}\).