Standard +0.8 This is a Further Maths parametric differentiation question requiring the chain rule formula d²y/dx² = (d/dt(dy/dx))/(dx/dt), involving trigonometric functions with powers. While the technique is standard for FP1, the algebraic manipulation with sec⁴t cosec t is non-trivial and requires careful simplification of multiple trigonometric identities, placing it moderately above average difficulty.