P3.4.4 - exponential

Understand and use exponential Students should be familiar with terms such as ‘initial’, growth and decay. ‘meaning when’ t = 0.; Students may need to explore the behaviour for large values of t or to consider whether the range of values predicted is appropriate.; Consideration of a second improved model may be required. d Knowledge and use of the result (ax) = ax ln a is dx expected.

Use exponential to connect the rule to the data and decision in the question.

This matters because exponential determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply exponential to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: exponential is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.