Trigonometry Flashcards

Flashcards for Trigonometry Review

Unit Circle

A circle with a center at (0,0) and a radius of 1.

Sine Function

Takes in an input of 𝜃, and gives an output of y of the point where the 𝜃 angle intersects the unit circle.

Cosine Function

Takes in an input of 𝜃, and gives an output of x of the point where the 𝜃 angle intersects the unit circle.

Reference Angle

The acute angle 𝜃′ formed by the terminal side of 𝜃 and the horizontal axis.

Tangent Function

Takes in an input of 𝜃, and gives an output of y/x of the point where the 𝜃 angle intersects the unit circle.

Cosecant Function

The reciprocal of the sine function.

Secant Function

The reciprocal of the cosine function.

Cotangent Function

The reciprocal of the tangent function.

Sine Function (Any Circle)

sin 𝜃 = y/r

Cosine Function (Any Circle)

cos 𝜃 = x/r

Tangent Function (Any Circle)

tan 𝜃 = y/x

Sine Function (Right Triangle)

sin 𝜃 = opp/hyp

Cosecant Function (Right Triangle)

csc 𝜃 = hyp/opp

Cosine Function (Right Triangle)

cos 𝜃 = adj/hyp

Secant Function (Right Triangle)

sec 𝜃 = hyp/adj

Tangent Function (Right Triangle)

tan 𝜃 = opp/adj

Cotangent Function (Right Triangle)

cot 𝜃 = adj/opp

Cofunction Identity

Cofunctions of complementary angles are equal.

Trigonometric Identities

Statements that are true for all input values on which they are defined.

Angle of Elevation

The angle measured upwards from a horizontal line.

Angle of Depression

The angle measured downwards from a horizontal line.

Domain

The set of all possible input values of a function.

Range

The set of all possible output values of a function.

Even Function

A function 𝑓 is even when f(-x) = f(x).

Odd Function

A function 𝑓 is odd when f(-x) = -f(x).