The light intensity III (in lumens) of a specialized lamp at a distance x x\,x meters is modeled by the function
I(x)=40x+3,x>0,x∈RI(x) = \frac{40}{x + 3}, \quad x > 0, x \in \mathbb{R}I(x)=x+340,x>0,x∈R
A control system adjusts the distance x x\,x based on a setting s s\,s according to the function
g(s)=52lns,s>1,s∈Rg(s) = \frac{5}{2} \ln s, \quad s > 1, s \in \mathbb{R}g(s)=25lns,s>1,s∈R
Determine, in simplest form, the value of the composite function Ig(e2)Ig(e^2)Ig(e2).
Find an expression for I−1(x)I^{-1}(x)I−1(x) and state its domain.
Hence, or otherwise, find all real solutions of the equation
I−1(x)=I(x)I^{-1}(x) = I(x)I−1(x)=I(x)
Practise Edexcel A Level Maths 2.4 Inverse Functions with exam-style questions for A Level Maths. 41 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.