P2.6.1 - Core trigonometric identities

Knowledge and use of sinθ tan θ =, cosθ and sin2 θ + cos2 θ = 1.

Use core trigonometric identities to connect the rule to the data and decision in the question.

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

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

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