Which side ratio gives sinx\sin xsinx in a right-angled triangle?
The tangent identity is tanx≡sinxcosx\boxed{\tan x\equiv\dfrac{\sin x}{\cos x}}tanx≡cosxsinx, where cosx≠0\cos x\neq0cosx=0.
Every side gains the same scale factor, which cancels in each ratio.
Taking a square root when finding cosine gives cosx=±1−sin2x\boxed{\cos x=\pm\sqrt{1-\sin^2x}}cosx=±1−sin2x; the quadrant determines the sign.
oppositehypotenuse\dfrac{\text{opposite}}{\text{hypotenuse}}hypotenuseopposite
1.4.5 Trigonometry Flashcards
Flashcards for CCEA A Level Maths 1.4.5 Trigonometry, covering the key formulae, methods and definitions you need to recall for AS 1, AS 2, A2 1 and A2 2. 20 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.