Paper 2 · Trigonometry ⏱ Tested in 5+ recent exam questions Lesson 8 of 9

LCOL Trigonometry 8: Cosine Rule

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You’ll learn

  • The cosine rule a² = b² + c² − 2bc·cos A is on…
  • Two sides + the angle between them → find the third side. Three…

Formula used

a² = b² + c² − 2bc·cos A

On page 20 of the log tables — read it off, don’t memorise.

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