A curve represents the thermal expansion of a composite alloy, where the length LLL is defined as a function of the temperature θ\thetaθ such that L=f(θ)L = f(\theta)L=f(θ). It is observed that the graph has a point of inflection at θ=185\theta = 185θ=185. Given that f′(185)=αf'(185) = \alphaf′(185)=α and f′′(185)=βf''(185) = \betaf′′(185)=β, where α\alphaα and β\betaβ are constants, identify which of the following statements must be true:
f′(185)=0 f'(185) = 0 f′(185)=0 f′′(185)=0 f''(185) = 0 f′′(185)=0 f′(185)≠0 f'(185) \neq 0 f′(185)=0 f′′(185)<0 f''(185) < 0 f′′(185)<0717 exam-style questions on Edexcel A Level Maths Differentiation, covering 9.1 Differentiating sin x and cos x, 9.2 Differentiating exponentials and logarithms, 9.3 The Chain Rule, 9.4 The Product Rule, 9.5 The Quotient Rule, 9.6 Differentiating Trigonometric Functions, 9.7 Parametric Differentiation, 9.8 Implicit Differentiation, 9.9 Using Second Derivatives, and 9.10 Rates of Change. Each one has a worked solution and a mark scheme showing where the marks go.