Unit Circle

What is the exact coordinates of  3π/4 on the unit circle?

• (−√2∕2, √2∕2)

• (−√2∕2, −√2∕2)

• (−√3∕2, −√2∕2)

• (√2∕2, −√2∕2)

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

• 1

• 0

• -1

• 1/2

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

• 1/2

• 0

• -1

• 1

What is the radius of the unit circle?

• 0

• 1

• 1/2

• √2/2

What is the radius of a unit circle?

• 1

• 2

• 1/2

• 0

Unlike right triangle trigonometry, sine and cosine may be negative. Thinking about how sine, cosine, and tangent relate to (x,y) coordinate pairs on the unit circle, find the quadrants where: cosine is positive: ​ (a)   ​& (b)   cosine is negative: ​ ​ (c)   &​ (d)  

• I

• IV

• II

• III

sin 2π/3

• 1/2

• -1/2

• √3/2

• -√3/2

Q1. What is the value of sin(30°)?

• A) -√3/2

• B) -½

• C) -√2/2

• D) -1

What is the value of sine at 210°?

• 1/2

• -1/2

• √3 / 2

• -√3 / 2