5.1 Trigonometric ratios

AQA Edexcel OCR A OCR B (MEI)
Sine, cosine and tangent are trigonometric ratios. Within a right-angle triangle:

  • Sine is the ratio of the length of the opposite side to the length of the hypotenuse;
  • Cosine is the ratio of the length of the adjacent side to the length of the hypotenuse; and
  • Tangent is the ratio of the length of the opposite side to the length of the adjacent side.

SOHCAHTOA


\(\sin{x} = \dfrac{O}{H}\qquad\cos{x} = \dfrac{A}{H}\qquad\tan{x} = \dfrac{O}{A}\)
Important
\(\sin{x} = \dfrac{O}{H}\qquad\cos{x} = \dfrac{A}{H}\qquad\tan{x} = \dfrac{O}{A}\)
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