Main Idea:

“Trig describes position and rotation.”

Coordinate Point Relationship

cos = x

sin = y

tan = $\frac{\text{y}}{\text{x}}$

on the unit circle:

Key Anchor Values

Every point on the unit circle is 1 unit away from the origin

*Watch this video to help: https://youtu.be/1m9p9iubMLU?si=_AxmOfA0CjISpQBN

*Watch this video to understand more about sin and cos (starts at 2:13): https://youtu.be/1m9p9iubMLU?si=TzuXlZ3Dxd8cLL2J&t=133

Zero Degrees

At $0^\circ$ the point is: (1 , 0)

Therefore:

• cosine = 1
• sine = 0

90 Degrees / (π/2)

Point: (0 , 1)

Therefore:

• cosine = 0
• sine = 1

180 Degrees / π

Point: (−1 , 0)

Therefore:

• cosine = -1
• sine = 0

270 Degrees / (3π/2)

Point: (0 , -1)

Therefore:

• cosine = 0
• sine = - 1

360 Degrees / 2π

Point: (1 , 0)

Therefore:

• cosine = 1
• sine = 0

1 full rotation completed.

The sign on cos and sin values can be positive or negative depending on the quadrant you fall in when trying to “extrapolate” your coordinate point on the circle.

Summary of the main idea: