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Exponentials and Logarithms

Exponentials and Logarithms

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Question 11

The temperature of water in a kettle is modelled using the formula T=75e−kt+22T = 75e^{-kt} + 22T=75e−kt+22

Where T T\,T is the temperature t t\,t minutes after the kettle is turned off and k k\,k is a positive constant.

a.

Find the rate of change of the temperature in terms of kkk

[2]
b.

After 5 minutes the temperature of the water is 70∘C70^\circ\text{C}70∘C. Find the value of kkk

[3]
c.

Find how many minutes it takes for the water to cool to 55∘C55^\circ\text{C}55∘C

[4]
Markscheme

Exponentials and Logarithms Questions

  1. AS Level
  2. /Maths
  3. /Exponentials and Logarithms

54 exam-style questions on Edexcel AS Level Maths Exponentials and Logarithms, covering 14.1 Exponential Functions, 14.2 y = e^x, 14.3 Exponential Modelling, 14.4 Logarithms, 14.5 Laws of Logarithms, 14.6 Solving Equations using Logarithms, 14.7 Working with Natural Logarithms, and 14.8 Logarithms and Non-Linear Data. Each one has a worked solution and a mark scheme showing where the marks go.

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