Sine waves

Basic trigonometry

Properties of a right triangle.

Sine

The ratio of the size of the opposite side to the hypotenuse.

The sum of all three angles of a right triangle is

180 degrees.

Ratio

For any given angle, there is a relationship with the sizes of the sides of the triangle.

Cosine

The ratio of the size of the adjacent side to the hypotenuse.

Tangent

The ratio of the opposite side to the adjacent side.

Right triangles are related to

unit circles

Unit circles

Divided into 4 quadrants and has a radius of 1.

Phase angle

The value describes how much of the period has elapsed.

Period

The time required for one complete cycle of rarefaction/condensation of a repetitive waveform.

Sine waves are created from

air molecule vibration and displacement, referred to as simple harmonic motion.

Simple harmonic motion and circular motion are related because

Circular motion, when viewed from the side, is simple harmonic motion.

Pure tone

The pressure of vibrating air molecules increasing and decreasing in a sinusoidal manner.

The amplitude of a sine wave is related to

the size of the source vibration.

Maximum condensation / compression

When adjacent air molecules are most densely packed together

Maximal rarefaction

When adjacent air molecules are spread out