TestMum
← 2021 HSC Extension 1 paper Question 14(b)

Variation 2 · answer guide

Differential equation — Different observation year

Question

Same DE and . If , set up the equation for (do not simplify numerically).

This practice question was inspired by Question 14(b) in the 2021 NSW HSC Mathematics Extension 1 examination, © NESA. It is an original TestMum variation that practises the same mathematical idea, not an official NESA question.

Step by step

  1. Set up the solution: separate or integrate the differential equation, include the constant, then use the initial condition., .
  2. Finish the calculation, then check that the result meets the question’s conditions..
  3. State the final answer clearly in the form the question requested.Equivalently .

Common mistake: changing so many features that the new example no longer tests the same mathematical idea.

Verification: Same reciprocal-elimination method.

Any mark labels are a TestMum study aid, not an official NESA marking allocation.

← Back to 2021 HSC Extension 1 paper Question 14(b)