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1.8 Exponentials and Logarithms

1.8 Exponentials and Logarithms

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Question 51

The total area, AAA hectares, affected by a wildfire is modelled by the formula

A=abt A = ab^t A=abt

where aaa and bbb are constants and ttt is the number of days after the fire was first detected at 6:00 AM on Monday. A graph of log⁡10A\log_{10} Alog10​A against ttt is plotted for the first 3 days. The data points form a straight line with a gradient of 0.14 and a vertical intercept on the log⁡10A\log_{10} Alog10​A axis of 0.85.

a.

Determine the value of aaa and the value of bbb according to the model, rounding your answers to two decimal places.

[3]
b.

Provide a practical interpretation of the constant aaa in the context of this model.

[1]
c.

Use the model to estimate the area affected by the wildfire at 6:00 AM on the following Saturday.

[2]
Markscheme

1.8 Exponentials and Logarithms Questions

  1. A Level
  2. /Maths
  3. /1.8 Exponentials and Logarithms

104 exam-style questions on OCR (MEI) A Level Maths 1.8 Exponentials and Logarithms, covering 1.8.1 The function y = a^x, 1.8.2 Convert between index and logarithmic form, 1.8.3 Logarithm as inverse of exponential, 1.8.4 Laws of logarithms, 1.8.5 Values of log_a a and log_a 1, 1.8.6 Solve equations of the form a^x = b, 1.8.7 Reduce y = ax^n and y = ab^x to linear form, 1.8.8 The function y = e^x, 1.8.9 Gradient of e^kx (A-level only), 1.8.10 The function y = ln x, and 1.8.11 Exponential growth and decay. Each one has a worked solution and a mark scheme showing where the marks go.

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