## Trigonometry

Trigonometry, abbreviated as TRIG, is a branch of mathematics that deals with the relations between the sides and angles of plane or spherical triangles. For other math terms see Algebra and Geometry.

## Mathematics Symbols

- See Algebra Symbols / Angle and Line Symbols / Basic Math Symbols / Bracket Symbols / Equivalence Symbols / Geometry Symbols / Greek Alphabet / Miscellaneous Symbols / Roman Numerals / Set Symbols / Square Root Symbols

## Mathematics Terms

## Nomenclature & Symbols for Engineering, Mathematics, and Science

- See A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

## Trigonometry Terms

- See A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

### A

**Arccos**- The inverse cosine.

**Arccot**- The inverse cotangent.

**Arccsc**- The inverse cosecant.

**Arcsec**- The inverse secant.

**Arcsin**- The inverse sine.

**Arctan**- The inverse tangent.

### C

**Cosecant (csc, cosec)**- The ratio of the hypotenuse over opposite side in a right triangle.

**Cosine (cos)**- The ratio of the adjacent side of the hypotenuse in a right triangle.

**Cotangent (cot, ctg)**- The ratio of the adjacent side to the oposite in a right triangle.

### H

**Heron's formula**- A formula for the area of a triangle when the lengths of the three sides are known.

**Hyporenuse**- The side of right triangle opposite the right angle, which is the longest side.

### I

**Infinite**- Having no boundary.

**Inverse statement**- Disaliow both the hypohesis and conclusion of the origional statement.

### L

**Law of cosines**- An equation relating to cosine of an interior angle and the lengths of the sides of a triangle.

**Law of sines**- The ratio of the sine of any angle within any specific triangle and the length for the opposite side is a constant.

### O

**Orthocenter**- The point of concurrence of the altitudes of the triangle.

**Orthogonal**- Perpendicular to a plane.

### P

**Pythagorean theorem**- An equation relating the lengths of the sides of a right triangle. The sum of the squares of the legs of a right triangle is equal to the square of the hypotenuse.

**Proportional**- In a constant ratio.

### R

**Ratio**- A constant proportion or two real numbers divided by each other.

### S

**Sine (sin)**- The ratio of the length of the opposite side to the length of the hypotenuse.

### T

**Tangent (tan)**- The ratio of the opposite side to the adjacent side of a right triangle.

**Tangent line**- A line that touches the graph of the function at a single point.

**Tangent of a circle**- A line that contacts an arc or circle at only one point.

**Trig functions**- sine, cosine, tangent, cosecant, secant, and cotangent

### X

**X-axis**- The horizontal axis on a coordinate system.

### Y

**Y-axis**- The vertical axis on a coordinate system.