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Differentiation of exponential and logarithmic functions — Question 279

Original QCE Vault practice · 5 marks

Q279 · Practice questionTechnology-activeSimple familiar5 marks

QUESTION 279 (5 marks)

A cup of tea has temperature T(t)=22+68e−0.12tT(t)=22+68e^{-0.12t} degrees Celsius, tt minutes after pouring.
a)
Determine its initial cooling rate.
[2 marks]
b)
Determine when it first reaches 50∘50^\circC. Give your answer to the nearest 0.10.1 minute.
[2 marks]
c)
Explain the role of the constant 2222 in the model.
[1 mark]
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