Introduction to Unit Circle

The unit circle...

• Has center at (1,1)
• Has a circumference of 1
• Has a diameter of 1
• Has a radius of 1

The hypotenuse of any right triangle from the center of the unit circle to an edge is always

• 1
• sqt2/2
• sqt3/2
• 1/2

Based on your unit circle sin(30^o)=

• sqt2/2
• 1/2
• 1
• sqt3/2

Based on your unit circle cos(30^o)=

• 1
• 1/2
• sqt3/2
• sqt2/2

Based on your unit circle cos(0^o)=

• 1
• 0
• -1
• 1/2

Based on your unit circle cos(90^o)=

• 1
• 0
• -1
• 1/2

Based on your unit circle sin(0^o)=

• 1
• -1
• 0
• 1/2

Based on your unit circle sin(90^o)=

• 1/2
• 0
• -1
• 1

Tangent is...

• a. Opposite/hypotenuse
• b. sine/cosine
• c. neither a or b
• d. both a and b

For what angles are sine and cosine the same?

• 0^o
• 45^o and 135⁰
• 45^o and 225⁰
• 45^o and 315⁰