# 1. unit circle for sec(-180 degrees) Choices are -1,0,1, undefined. 2. unit circle, find value for cos120 degrees Choices are sqrt(3)/2, 2 sqrt(3)/2, or -1/2 3. Exact value of sec(2pi/3) Choices...

1. unit circle for sec(-180 degrees)

Choices are -1,0,1, undefined.

2. unit circle, find value for cos120 degrees

Choices are sqrt(3)/2, 2 sqrt(3)/2, or -1/2

3. Exact value of sec(2pi/3)

Choices are -2sqrt3/3, -2, -1/2, or 2sqrt(3)/3 left.

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Student Comments

aruv | Student

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Unit circle

1. `sec(-180^o)=sec(180^o)=-1`

Correct answer= -1

2. `cos(120^0)=cos(90^o+30^o)=-sin(30^o)=-1/2`

Correct answer =-1/2

3. `sec((2pi)/3)=sec(pi-pi/3)=-sec(pi/3)=-1/2`

Correct answer=-1/2