noun

• The trigonometric function that is equal to the ratio of the side adjacent to an acute angle (in a right-angled triangle) to the hypotenuse.

  ‘If the two angles are the same we get the sines and cosines of double the angle.’

  More example sentences

  • ‘In fact, it corresponds to the graph of a function called the hyperbolic cosine.’
  • ‘I can remember roughly how to differentiate a standard xy formula but sines, cosines and tangents are a mystery.’
  • ‘Similar questions are investigated for the sine transforms rather than the cosine transforms.’
  • ‘The optical path difference is directly proportional to the cosine of the angle of refraction through the coating.’