A Level Maths: Trigonometry Topic Summary and Resources
Video Lessons
Watch alongside the worksheet for the full lesson experience, then test your understanding with the lesson questions.
Revision Notes
Handwritten notes summarising the key ideas for each lesson. Ideal for quick review before a test.
Exam Questions
Past-paper-style questions organised by topic, with full mark schemes.
- Sine and Cosine Rules and Area of a Triangle (OCR)
- Sine and Cosine Rules and Area of a Triangle (Edexcel)
- Introduction To Trigonometric Equations (OCR)
- Trigonometric Equations and Identities (OCR)
- Trigonometric Equations and Identities (Edexcel)
- Small Angle Approximations (OCR)
Drawn from OCR and Edexcel past papers but designed to be useful for students of all UK exam boards — including AQA and OCR MEI — unless a sheet is explicitly board-specific.
Before You Start This Topic
It will help if you are confident with the following:
- GCSE Maths Trigonometry — SOHCAHTOA and basic right-angled triangle work is assumed
- Surds — exact-value answers require fluent surd manipulation
- Quadratic Equations — needed for quadratic-in-trig equations
A Level Maths trigonometry is one of the broadest topics in Year 1 Pure, covering everything from basic sine, cosine, and tangent to identities, equations, and the sine and cosine rules. Confident trigonometry pays off across the entire syllabus — in Circle Geometry, Vectors, Differentiation, Integration, and all of mechanics.
You work with $\sin$, $\cos$, and $\tan$ for any angle (not just acute), using the unit circle and the symmetry of their graphs. You learn exact values at standard angles ($0$, $30$, $45$, $60$, $90$ degrees and their multiples), and use the identities $\sin^2(x) + \cos^2(x) = 1$ and $\tan(x) = \sin(x)/\cos(x)$ to simplify expressions and prove further identities. You solve trigonometric equations over given intervals, including equations that are quadratic in $\sin$ or $\cos$, and equations involving multiples of the unknown angle like $\sin(2x) = 0.5$. The sine rule and cosine rule let you find missing sides and angles in non-right-angled triangles, with the formula $\text{Area} = \tfrac{1}{2}ab\sin(C)$ for the area of any triangle.
Trigonometry is part of the Pure Maths strand of A Level Maths and underpins material throughout the rest of the course for AQA, Edexcel, OCR, and OCR MEI students.
Watch out for…
A few things to be careful with: when solving trig equations in a given interval, your calculator gives the principal value, but you need to use the CAST diagram or graph symmetry to find ALL solutions; for equations involving $2x$ or $x/2$, adjust the solution interval accordingly ($\sin(2x)$ over $0$ to $360$ means $2x$ ranges over $0$ to $720$); the sine rule has an ambiguous case where two triangles satisfy the given information; and degrees vs radians is a common slip — match the calculator mode to the question.