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anonymous
 one year ago
Evaluate the trig expression cos120 degrees
anonymous
 one year ago
Evaluate the trig expression cos120 degrees

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0\[\cos \left( 180\theta \right)=\cos \theta \]

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1hint: 120 degrees is in quadrant 2 (Q2) the reference angle formula for Q2 is R = 180x where x is the given angle and R is the reference angle

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1yeah so the reference angle is 60 degrees

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1now evaluate cos(60)

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1cos(120) = cos(60) keep in mind cosine is negative in Q2

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1make sure you are in degree mode

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Sorry if it's coming out weird. I don't have a scientific calculator (it broke) so I'm using the google calculator

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1type in "cos(60 degrees)" without quotes

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1google defaults in radian mode so you have to explicitly tell it to be in degree mode

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0\[\cos 60=\frac{ 1 }{ 2 }\]

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1so your final answer should be 1/2
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