Edexcel Mathematics October 2020 · Paper 2 · Question 9 · ExamRizz

ExamRizzEdexcel MathematicsMathematics

October 2020 · Paper 2 · Question 9 · 6 marks

9. A quantity of ethanol was heated until it reached boiling point. The temp erature of the ethanol, θ °C, at time t seconds after heating began, is modelled by the equation θ = A − Be− 0.07 t where A and B are positive constants. Given that ● the initial temperature of the ethanol was 18 °C ● after 10 seconds the temperature of the ethanol was 44 °C (a) find a complete equation for the model, giving the values of A and B to 3 significant figures. (4) Ethanol has a boiling point of approximately 78 °C (b) Use this informatio n to evaluate the model. (2) 25

Lesson: Exponential Functions and Their Graphs