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IB Maths AI SL 1.2 Arithmetic sequences and series

IB Maths AI SL 1.2 Arithmetic sequences and series
IB Mathematics: applications and interpretation guide, first assessment 2021

Identify the first term and common difference from the context, choose the nth-term or sum formula and check that the resulting index and units answer the question asked.

How this is tested

  • Use uₙ=u₁+(n−1)d to calculate a term or solve for the required index n.
  • Solve a contextual inequality to find the greatest or least valid sequence index.
  • Apply the finite arithmetic-series formula and interpret the accumulated total.

Question 1

[Maximum number: 5]

A marathon is a race over a distance of 42.19 km .

Question 1(b)

(a)

Find the week during which Rolando runs 42 km .

[ 3 ]

Question 1(c)

(b)

Find the total distance that Rolando runs in the first 10 weeks.

Davi runs 3 km in the first week. In each subsequent week he runs 20 % further than the previous week. These distances form the terms of a geometric sequence.

[ 2 ]