Definition of Cosine

Cosine

Jargon-Free Definition

A trigonometric ratio comparing two sides of a right triangle.

QCAA/AC9 Definition

The ratio of the adjacent side to the hypotenuse in a right-angled triangle.

Examples of Word Use in School

• Use cosine to Solve the missing side.
• Calculate .
• Choose sine or cosine for the problem.

Mathematical Definition

For an angle in a right triangle, .