The Unit Circle

Q U A D RA N T I

THE UNIT CIRCLE

REMEMBER

• Find the length of the missing side:

1 1 1

x

y

x

y

x

y

Aim: Use the unit circle in order to find the exact value of a trigonometric expression.

THE UNIT CIRCLE

• Draw a circle whose center at the origin, (0, 0), and has a radius of 1.

1

1

1

1

1

Aim: Use the unit circle in order to find the exact value of a trigonometric expression.

QUADRANT I

30°

( , )1

45°

( , )

160°

( , )

( , )

( , )

11

Aim: Use the unit circle in order to find the exact value of a trigonometric expression.

• Place Special Triangles into the first quadrant of the Unit Circle then label the points created.

Soh Cah Toa:Aim: Use the unit circle in order to find the exact value of a trigonometric expression.

CRITICAL ANGLE TABLE

0° 30° 45° 60° 90°

Sin

Cos

Tan

Aim: Use the unit circle in order to find the exact value of a trigonometric expression.

EXACT VALUE

The drawing of the Unit Circle (first quadrant) or the table just created can be used to find the exact value of the following trigonometric expression:

Find the exact value of

Aim: Use the unit circle in order to find the exact value of a trigonometric expression.