The Unit CircleDr. Shildneck

Fall, 2014

The Unit Circle

• The Unit Circle is a circle of radius 1-unit.

• Since angles have the same measure regardless of the size of their terminal side, we generally speak about their trigonometric ratios by using angles as they rotate around a unit circle.

Special Angles

0o

90o

180o

270o

360o

30o

45o

150o

135o

225o 240o

330o

315o

60o 120o

210o

300o

Special Right Triangles

30 – 60 – 90

45 – 45 – 90

1

2

3

1

1

2

x 2

x 3

x 2

=

Trig Values on the Unit Circle

11

1 1

Trig Values on the Unit Circle

1

Trig Values on the Unit Circle

11

1 1

Trig Values on the Unit Circle

1

Trig Values on the Unit Circle

11

1 1

Completing the Unit Circle

• Know the patterns for 45’s

• Know the patterns for 60’s

• Know the SIGNS (cosine – x, sine – y)

Completing the Table

• Know the Unit Circle (sines and cosines)

• Find Tangent (y/x = sine/cosine)

• Know Reciprocals

Assignment

1) Complete Unit Circle2) Complete Table

Practice more than onceDownloadable on Blog