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IB Maths AI SL 2.6 Modelling process

IB Maths AI SL 2.6 Modelling process
IB Mathematics: applications and interpretation guide, first assessment 2021

Students practise evaluating model validity by checking domain restrictions, asymptotic behaviour, sign consistency, and fit against real-world constraints.

How this is tested

  • reject a logarithmic word-count model at t = 1 because −167 + 6264 log₁₀(1) yields negative words
  • state that a phone depreciation model fails because hardware cannot remain functional indefinitely
  • compare r² values (0.766 vs 0.923) to justify why one temperature model fits data better

Question 5(c)

[Maximum number: 1]

The total cost, C(d), in Canadian dollars (CAD), to hire a bicycle for d days from Pedal Paradise is given by the function

C(d)=60d+10,d≥3,d∈ZC(d)=60 d+10, d \geq 3, d \in \mathbb{Z}

The total cost includes a fixed charge to hire both a helmet and a repair kit.

Write down the minimum number of days she can hire the bicycle.