# Trigonometry

This cheat sheet covers the high school math concept – Trigonometry. Trigonometry is a branch of mathematics that studies relationships between the sides and the angles of a triangle. The word “trigonometry” is derived from Greek words trigōnon meaning “triangle” and metron meaning “measure”.

Trigonometry is widely used in both pure and applied mathematics. It also finds applications in diverse fields such as physics, engineering, music, astronomy, ecology, and biology.

Trigonometry is generally introduced with right-angled triangles. This can be extended to any other type of triangle, by bisecting them to create two right-angled triangles. A cheat sheet on Properties of Triangles is also available on this website. It deals with many relations between the sides and the angles of a triangle.

This one page PDF covers summarised theory and the most important formulas related to the concept. Keep it handy while you’re revising the concept, especially before an exam.

The topics included in this cheat sheet are:

• Basic Trigonometric Identities
• Compound Angle Formulas
• Multiple Angle Formulas
• Sub-multiple Angle Formulas
• Sum to Product Formulas
• Product to Sum Formulas
• Miscellaneous Formulas