OCR AS Pure 2017 Specimen — Question 3

Exam BoardOCR
ModuleAS Pure (AS Pure Mathematics)
Year2017
SessionSpecimen
TopicExponential Functions

3 The number of members of a social networking site is modelled by \(m = 150 \mathrm { e } ^ { 2 t }\), where \(m\) is the number of members and \(t\) is time in weeks after the launch of the site.
  1. State what this model implies about the relationship between \(m\) and the rate of change of \(m\).
  2. What is the significance of the integer 150 in the model?
  3. Find the week in which the model predicts that the number of members first exceeds 60000 .
  4. The social networking site only expects to attract 60000 members. Suggest how the model could be refined to take account of this.