Given that nnn is a positive integer, express
52+3n−53n−2 \frac{5}{2+3\sqrt{n}} - \frac{5}{3\sqrt{n}-2} 2+3n5−3n−25as a single fraction not involving surds.
Hence, deduce that
52+3n−53n−2 \frac{5}{2+3\sqrt{n}} - \frac{5}{3\sqrt{n}-2} 2+3n5−3n−25is a rational number for all positive integer values of nnn.
532 exam-style questions on AQA A Level Maths 1.5 B: Algebra and functions, covering 1.5.1 Laws of indices, 1.5.2 Surds, 1.5.3 Quadratic functions, 1.5.4 Simultaneous equations, 1.5.5 Linear and quadratic inequalities, 1.5.6 Polynomials and rational expressions, 1.5.7 Graphs of functions and proportion, 1.5.8 Composite and inverse functions (A-level only), 1.5.9 Transformations of graphs, 1.5.10 Partial fractions (A-level only), and 1.5.11 Functions in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.