# Trig Identities Study Sheet

This study sheet has ten groups of trig identities for the basic trigonometry functions. These identities include the reciprocal and co-function relationships between trig functions. There are also half-angle and double angle identities, along with sum and product relationships. This table is an extremely useful thing to keep on hand when working with trig functions. Print a copy and keep it with your textbook today.

### Trig Identities

This cheat sheet is optimized to fit on a single sheet of paper. Download the PDF version to print your own. Alternatively, get the trig identities study sheet as a slide in Google Apps for viewing anywhere or sharing with classmates or students.

### Sine, Cosine, Tangent, Cotangent, Secant, Cosecant

The sine (sin), cosine (cos), tangent (tan), cotangent (cot), secant (sec), and cosecant (cos) of an angle θ are all ratios of the sides of a right triangle.

• sin θ = opposite / hypotenuse
• cos θ = adjacent / hypotenuse
• tan θ = opposite / adjacent
• cot θ = 1 / tan = adjacent / opposite
• sec θ = 1 / cos = hypotenuse / adjacent
• cos θ = 1 / sin = hypotenuse / opposite