A trigonometric identity is true for [ ] of the variable.
The reciprocal identity for cosecant is cosecx≡\cosec x\equivcosecx≡ 1sinx\boxed{\frac{1}{\sin x}}sinx1.
sin2x≡2sinxcosx\sin2x\equiv2\sin x\cos xsin2x≡2sinxcosx
A trigonometric identity is true for all permissible values of the variable.
Substitute the double-angle forms, then cancel to get sinxcosx\frac{\sin x}{\cos x}cosxsinx.
3.4.7 Trigonometry (A-level only) Flashcards
Flashcards for CCEA A Level Maths 3.4.7 Trigonometry (A-level only), covering the key formulae, methods and definitions you need to recall for AS 1, AS 2, A2 1 and A2 2. 22 cards, matched to the CCEA A Level Maths (2210) specification. Recall questions account for roughly 50% of marks at A Level Maths, so these target the marks you can secure before the paper starts.