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Trigonometry Reference Angles and Triangles Give an exact value for Cos 120º.
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Trigonometry
Reference Angles and Triangles
Give an exact value for Cos 120º.

User Bivas
by
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2 Answers

7 votes

Explanation:


cos \: 120 \degree \\ = cos \:( 180 \degree - 60 \degree) \\ = - cos \: 60 \degree \\ = - (1)/(2) \\ \\ \huge \purple{ \boxed{ \therefore \: cos \: 120 \degree = - (1)/(2) }} \\

User Nikes
by
8.4k points
4 votes

Answer:

-½

Explanation:

cos(120) = -cos(180-120)

= -cos(60) = -½

User JustColbs
by
9.6k points
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