Anonymous

# Unit circle help?

My answer was an educated guess.

Update:

I submitted the -1/2 and received a 2/3. I guess one of the parts of the question are wrong. Not sure which one. This question does not have the option of choosing a square root sign, only whole numbers... the first drop down is either a - or +, and the other two are numbers 1, 2, and 3

### 2 Answers

Relevance

- Anonymous2 months ago
The angle is 45 and exact value of cos(45°) is √(2) / 2.

They already give you the square root sign, so the drop downs are both 2

As the quadrant includes -1, the valency should also be minus.

- MichaelLv 72 months ago
tan 𝜽 = opp/adj

On the unit circle in QII

tan 𝜽 = -1 = 1 / (-1)

opp = 1

adj = -1

hyp = √(opp² + adj²)

hyp = √( 1² + (-1)² )

hyp = √ 2

Cos 𝜽 = adj / hyp

cos 𝜽 = -1/√2

Rationalizing the denominator

cos 𝜽 = -√2 / 2 <––––––

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