A theoretical model for the refractive index μ\muμ of a specialized optical glass depends on the incident light wavelength λ\lambdaλ according to the relation
μ(λ)=(1625+25λ)−32 \mu(\lambda) = \left( \frac{16}{25} + \frac{2}{5}\lambda \right)^{-\frac{3}{2}} μ(λ)=(2516+52λ)−23Determine the range of values of λ\lambdaλ for which the binomial expansion of μ(λ)\mu(\lambda)μ(λ) in ascending powers of λ\lambdaλ is valid.
308 exam-style questions on OCR A Level Maths 1.4 Sequences and Series, covering 1.4.1 Binomial expansion for positive integer n, 1.4.2 Link to binomial probabilities, 1.4.3 Binomial expansion for rational n (A-level only), 1.4.4 Validity of the expansion (A-level only), 1.4.5 Sequences (A-level only), 1.4.6 Increasing, decreasing and periodic sequences (A-level only), 1.4.7 Sigma notation (A-level only), 1.4.8 Arithmetic sequences and series (A-level only), 1.4.9 Geometric sequences and series (A-level only), 1.4.10 Sum to infinity of a geometric series (A-level only), and 1.4.11 Modelling with sequences and series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.