P3.2.3 - Knowledge

Knowledge and use of double angle To include application to half angles.; Knowledge of the formulae; use of formulae for t (tan 1 θ) formulae will not be required.; Students should be sin (A ± B), cos (A ± B) and able to solve equations such as a cos θ + b sin θ = c in a tan (A ± B) and of expressions for given interval, and to prove identities such as a cos θ + b sin θ in the equivalent cos x cos 2x + sin x sin 2x ≡ cos x. forms of r cos (θ ± a) or r sin (θ ± a).

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

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

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

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