$\tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)}$

$\pi \text{ radians} = 180^{\circ}$

$P = (\cos(\theta), \sin(\theta))$

$\sin(\theta) = \frac{\text{Opposite}}{\text{Hypotenuse}}$

$\cos(\theta) = \frac{\text{Adjacent}}{\text{Hypotenuse}}$

$\tan(\theta) = \frac{\text{Opposite}}{\text{Adjacent}}$

$\text{radians} = \text{degrees} \times \frac{\pi}{180}$

$\text{degrees} = \text{radians} \times \frac{180}{\pi}$

$x^2 + y^2 = r^2$, and since r=1, $x^2 + y^2 = 1$

$\theta + 2\pi k$, where k is an integer.

Sine: y-coordinate on the unit circle, odd function | Cosine: x-coordinate on the unit circle, even function

Positive angles: Measured counterclockwise | Negative angles: Measured clockwise

Radians: Based on the radius of the circle, dimensionless | Degrees: Arbitrary division of a circle into 360 parts

sin(0) = 0 | cos(0) = 1

sin(π/2) = 1 | cos(π/2) = 0

Sine: [-1, 1] | Cosine: [-1, 1]

y = sin(x): Starts at (0, 0), odd function | y = cos(x): Starts at (0, 1), even function

Derivative of sin(x): cos(x) | Derivative of cos(x): -sin(x)

Integral of sin(x): -cos(x) + C | Integral of cos(x): sin(x) + C

Sine: Opposite/Hypotenuse | Cosine: Adjacent/Hypotenuse

A circle with a radius of 1, centered at the origin (0,0).

An angle that starts from the positive x-axis and goes counterclockwise.

A unit of angular measure equal to the angle subtended at the center of a circle by an arc equal in length to the radius.

A line from the origin at a given angle that intersects the unit circle.

The y-coordinate of the point where the terminal ray intersects the unit circle.

The x-coordinate of the point where the terminal ray intersects the unit circle.

The ratio of the y-coordinate to the x-coordinate (sin θ / cos θ) of the point where the terminal ray intersects the unit circle.

Angles greater than 180° but less than 360°.

2π radians.

A mnemonic to remember which trig functions are positive in each quadrant: All, Sine, Tangent, Cosine.