Unit Circle

sin(30^o)=

• sqt2/2

• 1/2

• 1

• sqt3/2

sin(150^o)=

• sqt2/2

• 1/2

• 1

• sqt3/2

cos(2π/3)

• -√2/2

• √3/2

• -1/2

• 0

• cos pi/6
• sin pi/4
• cos pi/3
• tan pi/4

Which angle satisfies the equation cosx = 0? Select all that apply

• x = π/2

• x = π

• x = 240º

• x = 270º

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

• 1/2

• undefined-1

cos(π)=

• 0

• 1

• -1

• 1/2

Which of the following is a coterminal angle of 165 degrees?

• 195

• 525

• -525

• -190