OCR A Level Maths: Pure

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5.1.1 Trigonometry - Definitions

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Trigonometry - Definitions

What is trigonometry?

  • Trigonometry looks at the relationship between side lengths and angles of triangles
  • It comes from the Greek words trigonon meaning ‘triangle’ and metron meaning ‘measure’
  • The three trigonometric functions Sine, Cosine and Tangent come from ratios of side lengths in right angled triangles

 Trigonometry - Definitions Diagram 1, A Level & AS Level Pure Maths Revision Notes 

What is the unit circle and how does it help with trigonometry?

  • The unit circle is a circle with radius 1 and centre (0, 0)
  • It can be used to calculate trig values as a co‑ordinate point (x, y) on the circle
  • (x, y) = (cos θ, sin θ), where θ is the angle measured anticlockwise from the positive x‑axis
  • It allows us to calculate sin, cos and tan for angles greater than 90°

 

Trigonometry - Definitions Diagram 2, A Level & AS Level Pure Maths Revision Notes

Worked example

Trigonometry - Definitions Example Question, A Level & AS Level Pure Maths Revision Notes Trigonometry - Definitions Example Solution, A Level & AS Level Pure Maths Revision Notes

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