GCSEMaths

GCSE Maths Trigonometry Revision Notes

Master GCSE Maths Trigonometry using simple revision notes, key facts and practice questions — all generated by AI for your exam.

Trigonometry is a branch of mathematics that deals with the relationships between the angles and sides of triangles, particularly right-angled triangles. It is essential for solving problems involving angles, distances, and heights.

Key Concepts

  • 1The primary trigonometric ratios are sine (sin), cosine (cos), and tangent (tan).
  • 2In a right-angled triangle, sin = opposite/hypotenuse, cos = adjacent/hypotenuse, and tan = opposite/adjacent.
  • 3The Pythagorean theorem states that in a right triangle, a² + b² = c², where c is the hypotenuse.
  • 4Trigonometric ratios can be used to find unknown angles and lengths in right triangles.
  • 5The unit circle is a helpful tool for understanding trigonometric functions and their values.

Simple Explanation

Trigonometry helps us understand the relationships in right-angled triangles. The three main functions are sine, cosine, and tangent, which relate the angles to the lengths of the sides. For example, sine tells us how the length of the opposite side compares to the hypotenuse. By using these functions, we can find missing angles or side lengths in triangles.

Memory Trick

Remember 'SOH-CAH-TOA' to recall the definitions of sine, cosine, and tangent: Sine = Opposite over Hypotenuse, Cosine = Adjacent over Hypotenuse, Tangent = Opposite over Adjacent.

Flashcards

Question1 / 5

What does SOH-CAH-TOA stand for?

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Exam Questions

Describe and explain how to use trigonometric ratios to find an unknown side in a right triangle. [6 marks]

6 marks
View mark scheme hint

Define trigonometric ratios, explain which ratio to use based on given information, show calculations, and conclude with the found length.

Explain how the Pythagorean theorem relates to trigonometry. [4 marks]

4 marks
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Discuss the relationship between sides of a right triangle and how it supports trigonometric functions.

What is meant by the term 'hypotenuse'? [2 marks]

2 marks
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Define hypotenuse as the longest side of a right triangle opposite the right angle.

Practice Quiz

Question 1 of 5Score: 0

What is the sine of an angle in a right triangle?

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