A biologist models the concentration ratio, RRR, of two specific enzymes in a cell culture over time ttt (in hours) using the function
R(t)=8t2+6t−54t2+5t+6+16t+2,t∈R, t>1 R(t) = \frac{8t^2 + 6t - 54}{t^2 + 5t + 6} + \frac{16}{t + 2}, \quad t \in \mathbb{R}, \ t > 1 R(t)=t2+5t+68t2+6t−54+t+216,t∈R, t>1Show that R(t)=8t−2t+2R(t) = \frac{8t - 2}{t + 2}R(t)=t+28t−2.
Show, using calculus, that RRR is an increasing function. You must make your reasoning clear.
The function hhh is defined by
h(x)=1+lnx,x≥1 h(x) = 1 + \ln x, \quad x \ge 1 h(x)=1+lnx,x≥1Find h−1(x)h^{-1}(x)h−1(x), stating its domain.
Determine the exact value of aaa for which hR(a)=2hR(a) = 2hR(a)=2.
566 exam-style questions on OCR A Level Maths 1.2 Algebra and Functions, covering 1.2.1 Indices, 1.2.2 Surds, 1.2.3 Simultaneous equations, 1.2.4 Quadratic functions, 1.2.5 Completing the square, 1.2.6 Solving quadratic equations, 1.2.7 Inequalities, 1.2.8 Expressing solutions of inequalities, 1.2.9 Representing inequalities graphically, 1.2.10 Manipulating polynomials, 1.2.11 Simplifying rational expressions, 1.2.12 The modulus function (A-level only), 1.2.13 Graphs of functions, 1.2.14 Sketching curves from equations, 1.2.15 Sketching reciprocal curves, 1.2.16 Interpreting solutions graphically, 1.2.17 Intersection points of graphs, 1.2.18 Proportional relationships, 1.2.19 Graph of the modulus of a linear function (A-level only), 1.2.20 Solving modulus equations graphically (A-level only), 1.2.21 Definition of a function (A-level only), 1.2.22 Inverse and composite functions (A-level only), 1.2.23 Simple graph transformations, 1.2.24 Combinations of graph transformations (A-level only), 1.2.25 Partial fractions (A-level only), and 1.2.26 Models in context. Each one has a worked solution and a mark scheme showing where the marks go.